Number 200. Argh!

There is not enough time in the day, so I have to ask you. (Please don't ask me to do another search... )

So far, I understand that the folks who are installing this indicator light are splicing a wire into circuit #480, which is a violet wire with a yellow tracer that leads from the connector at the right side of the transmission, down near the pan, at connector #C1048, up to Connector #C103 on the left side front wheel well, up to Connector #C1027, Pin 54, at the back of the PCM in the firewall. The PCM, under the programmed conditions, "gounds out" the signal in this #480 circuit, which in turn engages the TCC (Torque Converter Clutch).

Do I have this correct so far?

Now, on to this LED. Crewzer mentioned something about the "anode" and the "cathode" of the LED, and which end to hook to 12 volt power (the anode), and which end to splice into circuit #480 (the cathode). Well, when it comes to electronics, my mind is usually lost at sea. Speaking of the sea, I know about cathodes and anodes for rust prevention in yachts, but er eh... my 2001 Radio Shack catalog (page 256) says nothing about cathodes and anodes amoung all the LED choices they have listed on that page. Some of the 12 volt LEDs have a red and a black lead... so which is the Cathode and which is the Anode?

But most of the 12 volt LED's have unmarked leads, both are either black or uninsulated. They seem impossible to differentiate from one another. Does it matter which end goes where on these LEDs?

Like I said, I am a little lost when it comes to electronics. I never have seen an electron, so I can't confirm that they even exist. But I'll take it on faith... whatever you tell me.

And, by the way, if I have a 12 volt power supply connected to the LED, does the lamp not only serve as a resistor, but function as a diode as well? How do I make sure that I am not inducing any current or voltage to circuit #480 that the PCM or the TCC solenoid is not expecting?

A lot of people have done this mod, so there must be a harmless and efficient way to execute it... Right? Please make it painstakingly clear... Thanks!

By the way, I gotta tell ya, reading all 200 of those posts about when the TC is locked and unlocked... I couldn't tell you the difference in my truck from when the Torque Converter Clutch is engaging, versus when the Coast Clutch is engaging or disengaging.
For all I know, it all sounds and feels like shifty business to me. I think an indicator light of some sort will better acquaint me with the distinctions of shifting versus lockup engagement/disengagement.

I hope this thread ends up as an easy to search and find reference repository of how-to information for others who wish to add this feature to their creature. So please, post your DETAILS, never mind if you have posted them before. A wiring mistake here would make for an expensive lesson in basic electonics.

Thanks in advance for your replies.

Robyn-

HERE are some wonderful wiring diagrams, created by Bearsweasel...they might be of some help...

I have the TC lockup and EB wired similarly to BW's diagrams, but I, too am lacking in electronics knowledge.

FYI- unless you are intent on wiring up an led with a resistor inline with it, I suggest you simply purchase a LED with the "prewired resistor" from Radio Shack...

So far, I understand that the folks who are installing this indicator light are splicing a wire into circuit #480, which is a violet wire with a yellow tracer that leads from the connector at the right side of the transmission, down near the pan, at connector #C1048, up to Connector #C103 on the left side front wheel well, up to Connector #C1027, Pin 54, at the back of the PCM in the firewall. The PCM, under the programmed conditions, "gounds out" the signal in this #480 circuit, which in turn engages the TCC (Torque Converter Clutch).

Do I have this correct so far?

your description seems accurate...but you ought to consider wiring in a switch to manually override the PCM control of the TC...it really works great!

I wish that I could give you a simple 'how to', but I added the lock without the LED...but if you haven't previously found the diagrams (above link) then I feel those to be VERY helpful.

good luck!

Be sure you have the type of LED with a built in dropping resistor, i.e., made to run on approximately a 12v circuit, or the LED will light up exactly one time . Otherwise a dropping resistor will need to be added if the LED does not have one (try around 330ohm, depends on the continuous forward current rating of the LED and environmental conditions [temperature derating]. 330 is good for about 40mA, use in the vicinity of 600 for 20mA).

If you have an LED with a dropping resistor, but don't know the polarity (well, if I remember correctly the longer lead is usually positive/anode, opposite the flat on the case) use 1.5V or 3V battery and see which way lights the LED. Might not be very bright, but it will only light one way (OK, except for some types which are actually 2 LEDs in one case, and will light both ways... Don't know if RShack sells those).

The following might be of some help to you.

This was done on my 2000 PSD.

Part #1 (Converter Lock LED):

Check out "FAQ" on this Ford-Diesel.com site. Then go to "1999 and up," then to "Torque Converter Diagram." This will show you the # 54 pin and the wire color (which I will now refer to as the purple with a yellow tracer).

This whole thing works because the computer provides a "Ground" for this purple with yellow tracer wire when it commands the converter to lock up. The 12 volt L.E.D. is connected to 12 volts on one side and to the purple with yellow tracer on the other, so when the computer provides a ground, the converter locks and the L.E.D. lights.

It's very interesting to watch this thing work. Just when did the converter lock/unlock. I watch it as much as I do the other gauges. In the mountains on up/down grades, it is very helpful.

I found the proper wire (purple with a yellow tracer) at the transmission plug (passenger side). Once I know which wire I wanted, I looked for the best place to make the connection. This wire enters a "plastic wire wrap" which runs over the top of the transmission to the drivers side of the frame, then along the frame up to the computer plug.

There is a lot of room to easily work with and make the connection to this wire where it runs along the frame over the top of the fuel pump location. Just pull the plastic wire wrap open and locate the proper wire.

The 12 volt L.E.D. pulls only a few milliamp (almost nothing) so the connection is simple. I just used a small pin and pushed a small hole through the (purple with a yellow tracer) wire. Then slipped only 2 strands of the connecting wire (from the L.E.D.) thru it, with the ends wrapped around the purple with a yellow tracer control wire to hold everything in place. This is all the connection you need. Wrap the connection and place everything back inside the plastic wire wrap, including the wire you just added, and replace the tape over the black plastic wrap. Everything fits and you end up with a neat, protected, factory-look installation.

Don't experiment, make sure your comfortable with what your doing. You're working with wires that run to the computer and a mistake could be disastrous. Just make sure you are connecting to the right wire.

Part #2 (Additional control for Western Diesel Turbo Brake)

About a year ago I installed (Part #1) an LED to light when the converter locks/unlocks.

When towing my Fiver, I have been happy with the Western Diesel Turbo Brake except:

When the brakes are applied the Torque Converter unlocks. I would prefer that it stayed locked to help with the brakeing.

When in 3rd with the Turbo Brake on, I would prefer to see the converter not unlock when the speed drops to 40 mph.

I have now added a Toggle switch in series with a Monentary switch to the LED circuit. One side of the Dash Mounted toggle switch is connected to the LED (Torque Converter side). The other side of the toggle switch goes to the monentary switch. The other side of the monentary goes to ground. The monentary switch is left foot operated.

The toggle switch is there as a safety switch. When off, the foot controll is also off.

When the toggle switch is "ON", simply press on the monentary foot switch whenever you wish to have manual control of the torque converter. The converter will now stayed locked when you use your brakes. Press and hold the foot switch will also keep the converter locked as the speed drops under 40 mpr for additional exhaust brake action.

Obviously, do not press the foot switch at very slow speeds. The converter must be unlocked or the engine will stall. Why would you? There is no need to.

This is something that works well for me on my 2000.

Pic of mounted Foot control switch is in Photos below by the Dash pictures.

As noted, an LED is designed to have current flow in one direction, from anode to cathode. The suggestion to use a 1.5V battery to determine polarity is a good one.

LEDs are fairly straightforward when operated in a continuous DC environment. The spec for the device should include forward voltage (the voltage drop across the LED) and current (in milliamps, or mA). For LEDs that don't include a dropping resistor, you can use this info to calculate your own.

Let's say that your LED has a forward voltage of 1.7VDC at 20 mA (0.02A). To use this device in a 13VDC system, you've got to get rid of 11.3VDC by using an external dropping resistor.

Using Ohm's Law, V/I = R, or 11.3V/.02A = 565 Ohms; I think 560 is a standard value (I used to know that stuff by heart). There will some heat dissipated (11.3V X 0.02A = 0.226W, so a 1/4W resistor is marginal and a 1/2W would be better. The resistor should be wired in series with the LED; either side is OK.

You're LED's specs may be different, but you can substitute them in to the equations above to solve for your requirements. To aid in your comfort factor, I'd suggest hooking the LED and resisitor to a 12V battery to make sure it's OK.

BTW, the TCC circuit in the PCM will be required to sink the additional ~20mA through the LED. However, this is trivial compared to the 300 mA or more required to latch the TCC relay, so I wouldn't worry about it. Properly installed, the LED will only come on when the TCC lock circuit is activated, and it will not affect the operation of the TCC.

I've not yet installed a TCC indicator on my 250. I did, however, install one in my ol' 1986 Suburban, and it worked flawlessly for 10 years (better than can be said for the sub! ).

Please feel free to e-mail me directly if you still need more info. I'd be happy to draw/scan a schematic and fax/e-mail it to you.

Regards,
crewzer

As Crewzer I believe has correctly stated is that this LED circuit affects the normal operation of the PCM controlled circuit and one must be careful to ensure to the maximum extent that these affects are kept to the minimum. Thus I would think that the following might be prudent in designing this LED circuit and any circuit that manually grounds this circuit.
1. Use the lowest current draw LED (some are as low as 2 ma or as high as 60 to 70 ma according to my RS catalog) with the highest dropping resistor to allow the LED to operate would be the way to go.
2. Consider use of an extremely low draw relay such as RS 275-233 reed relay which has a 11ma coil rating as the switching device for this LED circuit.
3. Finally, consider as an extra safety measure to fuze +12V source to this LED circuit with the lowest possible fast acting fuze you can find.

Just my thoughts, and I don't want to scare anyone, but just because something seems to work doesn't necessarily mean it is smart or well designed. Remember we're doing something here that the original designers did not account for - there might be a lot more going on here than meets the uniformed eye. I.E. the PCM unlocks the TC when the speed drops to a certain level and I'm sure there are other things going on too, which we are all unaware of. Thus IMHO every safety measure is not only prudent, but absolutely necessary.

Anyone especially Crewzer that can provide more information on the acutal operation of this circuit could be extremely invaluable.
Since I am still patiently waiting for my PSD I don't have the luxury of actually playing with real hardware - see my sig

Larry is right that we need to careful when fooling around with expensive subsystems like the PCM. However, my view in this case is that adding the LED and resistor as discussed is a very, very low risk enterprise. Here's why:

1) The circuit is quite simple in that an LED, along with a current-limiting resistor, is being added in parallel to another simple component, the TCC relay. Except for the PCM itself, there are no other components involved.

2) The open-loop circuit is so simple that calling it a "TCC lock indicator" isn't actually correct. It's really a "the TCC has been told to lock" indicator, as that's really all that's happening and we have no confirmation from the TCC that it's actually locked (a closed-loop system).

3) The circuit is binary: either it's active (told to lock) or inactive (not told to lock), and there's no other activity, either direct ot indirect.

4) It's been done by me on other vehicles as well as by F-D.com members on their SDs with no apparent detrimental side effects.

5) If the LED with its resistor is installed backwards, it not only won't work, but it won't cause any damage because the LED will block the +12 to ground current flow.

6) LED's open when they fail, which, by the way, is very rare. When this happens, the circuit is opened and there's no current flow, the exact opposite of a short circuit.

The addition of a relay and/or a fuse introduces the potential for new problems, as adding more components always adds complexity and reduces reliability. Ironically, the relay itself could harm the PCM through a kick-back voltage induced by the coil's collapsing electro-magnetic field when the relay is de-energized. The normal solution to this issue is to add an anti-kick-back diode in parallel to the relay coil and in reverse polarity. To be fair, however, this is normally only a problem with high-current relays and coils, such as the AC clutch.

Larry, I hope you understand I'm not trying to argue with you over this topic. Rather, I'm trying to allay your concerns, which are quite valid, and provide the info and support to you and other fellow members who are interested in adding this useful feature.

I'll add this feature to my truck as well at some point. Generally, I can confirm the TCC lock by "feel", sort of like an extra shift, especially in third and fourth gears. Also, my tach clearly shows the resulting reduction in engine speed. My old Sub had no tach and the AT was problematic, so the indicator was a true necessity.

Hope this helps, and more info later.

Meantime, several people asked about Radio Shack part numbers of LEDs and resistors and what-not. Now THAT I can handle...

LED's

I've got three Radio Shack LED's with red and black wire leads sitting here on my desk.

276-270A Red
276-271A Green
276-272A Orange

I couldn't decide which color I wanted to use, so I bought all three. Actually, I thought I might have one LED brighten when in TC Lockup, one brighten when I had a TCC overide switch on, and one brighten if a thermostatically preset temp limiter engaged, such as on a tranny cooler electric fan. With all the PSD racket, I might not ever hear an electric fan, and it would be nice to have confirmation when it kicks on.

Anyway, here are the specs that apply equally to the three Radio Shack LEDs listed above:

Forward (Supply) Voltage: 12.0 VDC typical

Maximum Voltage: 16.0 VDC

Maximum Current: 15.0 mA (milliamperes)

Lens Size: 8.5 millimeters
Hole Size required to drill: 9/32"

Each of these LED's are packaged as a total assembled kit, complete with lead wires, lens, mounting nut, lockwasher, sealed case body, and RESISTOR. Let's talk about these resistors for a second, and maybe you can help sort these out.

Resitors

These are axial lead resistors that are wire wound. (I am assuming "wire-wound" because the "A" band is wide) The colors of the bands are somewhat hard to determine, because the resistors are encased and sealed with silicon within the body of the lamp assembly, which is colored the same as the lense. So we have this additive color lensing thing happening here... which makes a HUGE, potentially misleading ohm calculation difference in interpreting the colors. For example, the "C" band mulitplier through the green lens body looks to be either brown or violet. Well, that could mean times ten if brown, or times a million if violet.

After staring at these for a while, holding them up to different lights, my best guess is that band "A" is light blue (6), and band "B" is either blue (6) or green (5). So, the question is: if the resistance is 650 ohms... or 6.5 megaohms... neither of which sound exactly right to me. But then again, I've never seen an electron, and don't really know what they look like, let alone how to size them up. In fact, I'm not even sure how relevant this resistance is when dealing with an already made up LED kit, as opposed to a raw LED component, so I am hoping that you can sort this out and post your clarifications.

Due to the color lensing effect, the bands of each of the resistors in the three lamps look a little different. It is therefore possible that the bands could be actually different among the three resistors, as much as it is possible that the resistors are all the same, and only look different due to the color lense.

One final note on the resistors. The tolerance band (band "D") was silver in every case, indicating a 10% tolerance. Only this silver band was not really in the "D" position... it was all the way over by the end lead.

LED Ergonomics

Here is some other specification data that I decided to bog myself down with, to attain adequate lamp visibility during the day, while maintaining driver safety (sufficient dimness) at night:

Luminous Intensity:
"Average, or typical, light output at the rated maximum current"
Red: 33 mcd (millicandles)
Green: 24 mcd
Orange: 23 mcd

Peak Emmission Wavelength:
"Wavelength at which the majority of light is emitted"
The packages all say the same thing... 585 nm typical... but the catalog says:
Red: 635 nm typical
Green: 565 nm typical
Orange: 585 nm typical

Viewing Angle:
"Angle between half-intensity points on either side of direct viewing"
All three LEDs: 25 degrees.

Short of posting a picture of these LED lamp assemblies, that is about all I can tell you about them. Radio Shack does offer many more LED's than just these three. In fact, I counted 46 other LED's available. Yet for a variety of reasons, I felt that the three cited above were the best available for the application that this whole thread is about.
Some of those reasons include:

1. Ready made lamp assembly, including threaded sealed case, and mounting hardware.

2. Red and black leads, for no-brains-nitwits like me who wouldn't know an anode if it was removing the rust from my head.

3. Low current draw, at 15 mA. Radio Shack certainly offers other "ready made" lamp assemblies, but they range from a minimum of 25 mA up to 95 mA at the 12 volt level. Some of the non-LED minilamps did not list current ratings in the catalog, but I think LEDs would last longer than neon or miniature incandesents.

4. Appropriate running voltage, at 12 volts. Of the 46 LEDs, many were rated at 1.7 to 3.6 VDC... so that rapidly narrowed the selection down to less than 15.

4. High maximum voltage, at 16 volts. This seemed appropriate for an automotive charging environment, that typically might run at 14.1 volts.

5. Built-in flange... for secure mounting

6. Radiused profile... for smooth looks.

How's my sales pitch coming along ?!?!?

Too bad I still can't drum up the courage to wire them in though...

A Special Thanks to Roger "The Web" and Crewzer... for contributing what to me was indecipherable Chinese, er ahem, pardon ...make that excellent essays on how to wire this up! What is so sad is that Roger himself personnally took me on a tour of his truck, and explained to me face to face what he had done, this after I had already printed out and studied his post contemporaneous to the time that he posted it originally... and I STILL feel lost... or at least a little nervous... about doing it myself. I wouldn't want to venture into something I still don't quite understand... I have molasses for a mind.

quote:

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Originally posted by crewzer:
I recommend using a green LED for this application as locking the TCC is (supposed) to be a "good thing".

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Another good thing about the GREEN LED, if you noticed the stats from my post previous, is that it is not as bright as the red LED, making it less distracting at night. This is important, as a "TC Locked" LED will likely be "ON" a lot more than it will ever be "OFF," when "crewzing" down the highway.

I did indeed receive your e-mail including the offer of the 2001.5 guide, and I e-mailed back right away... dunno what happened (I thought maybe the e-mail ended up in a box of old film ), but will re-transmit tonight .

Back to LEDs; you're progressing well.

The resistor on the 12V LED is most certainly in the 650 Ohm range. At 12 V, VERY little current would pass through a 6.5MOhm resistor (formula is I = V/R).

The LEDs you've selected will work fine for the applications we're discussing here. At some point, I'll sit down a figure out a way to hook them into the dash illumination dimming circuitry.

If a green LED is to be used for the TCC lock indicator, then I recommend you consider orange for the thermostatically preset temp limiter, as we have been conditioned to associate orange (or yellow) with "caution".

Let me make another comment. I'm very comfortable with the idea of adding low-current lamps in parallel to various circuits, such as the TCC lock, as a means of indicating their operation.

At the moment, however, I'm equally uncomfortable with getting involved in the manual override TCC locking experiments, and I'm going to abstain for a while. Let me just leave it at that.

Robyn - As to you investigation and excellent treatise on LED's one thing you seemed to be concerned about was visibility. In this regard one thing that you might find useful is to take which ever LED you are considering using and wiring it up to a 12V plug that goes into the cigarette lighter and go and sit in your vehicle during day and night time conditions, plug in the LED and hold it where you plan to mount it and see if the level and visibility is acceptable to you. This way you can pretend that you are driving and while in a normal driving position see if the LED would catch you attention have an acceptable level of intensity. As you found out in you LED ergonomics, LEDs have a certain viewing angle and as such their location and orientation can affect their visibility. This was one reason that I am still considering a little different indicator system using a 12V pilot lamp assembly using a relay such as the one I previously mentioned along with a dimmer switch to ensure that I have the acceptable brightness during the day and dimness at night. For me this solves the orientation problem with using an LED and my current idea is to mount this in the 4 guage A-pillar that is also on by list of to do when I finally have the luxury of getting into a real vehicle. Also this would allow me to simply unscrew the pilot lamp if I need to take the vehicle in for warranty service so that lights would not go off that the tech did not understand. As Crewzer correctly states this makes the system more complex and adds some reliability issues which each of us must consider and then individually decide on what we feel is the best thing to do. As to fuzing I personally always fuzes systems that I design and install just look at your vehicle and the number of fuzes used. Even if I we're to use an LED for an indicator, I would in my installation still install a fuze such as RS270-1055 (.063A=63ma) in an inline fuze holder.

As to the three LED's you chose I will let others comment since I obviously have not actually done this mod, but looking at my RS cataloge you have chosen an LED with a current draw on the lower end of what is avaliable which IMHO can only be good. You may not have the luxury but, I always hook up my systems to my handy multimeter and measure the current draw of what I am designing. This way, I like you have never seen an electron and wouldn't know one it I ever did see it, so I depend on others more qualified than me - "My handy multimeter" to do this task.

These are just my thoughts and please anyone interested feel free to disagree - I will never take and none of us should ever take offense when one is expressing their opinions and thoughts - just as Crewzer did - this is how we learn and that is never bad.

P.S. My first post on this topic was very much in line with my thinking when I started the thread in the Upgrades and Aftermarket forum titled "~50 exhaust brake current requirements" which has generated some interesting information. There again I was simply elicitating information so I can better understand what I might consider doing. Sorry, I would have put a link in here but haven't figured out how - I have a hard enough time simply hitting the right keys on my computer.

Any more "meat and potatoes" out there???

quote:

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Originally posted by vanman_psd:
You may not have the luxury but, I always hook up my systems to my handy multimeter and measure the current draw...

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It ain't the luxury that I lack... it's the presence of mind. It hadn't occured to me to actually MEASURE. Heaven Forbid. My neighbor has his own engine dynometer in his shop. The sign on the big panel of guages says "Test, Don't Guess!" Thanks for the reminder! In fact, thank you Larry, for all of your great contribution of ideas to this thread.

Now, more meat and potatoes...

With my "handy" autoranging digital volt/ohm/amp meter ... (in truth, mine wasn't quite so handy, I had to first find the darn thing, and then vacuum the cobwebs off it)... I made a number of measurements to evaluate these LEDs. By this time, Roger must be rolling on the floor laughing outloud, wondering why we just don't hook it up and be done with it??

Well, my 12v power supply was a 1 amp charger, with 15.51 output voltage DC... making those LEDs glow using from 18.82 to 19.21 mA of current. Resistance could not be checked... the circuit appears wide open unpowered. However, these LED's do seem to funtion as diodes, registering a Forward Bias Voltage reading of 1.718 volts with the leads in correct polarity. With the polarity reversed, the meter read open.

The narrow (25 degree) viewing angle is good for me, as LEDs appear quite bright when directly shown to the eye.

But none of this gobbledygook gives me any more confidence in succeeding with this installation, and here is why.

First, let's talk about this "purple and yellow" wire. There is more than just one purple and yellow wire in THE SAME HARNESSES as the wire we want. Circuits #870 and #771 are BOTH violet with a yellow tracer, and BOTH run in wire Harness #12A581 and #15525... right alongside Circuit #480, which is the wire we're after. Circuits 870 and 771 control transfer case funtions.

That Roger was able to select the correct conductor within the harness at the fuel pump location, ahead of both the transfer case and the transmission, can only be a testament to his mysterious electrical powers!

I am reasonably confident that I can distinguish between these same colored circuits at the group of four parallel connectors on the driver's side wheel well. There, it is easier to see which purple and yellow wires enter Connector #1044, and which wire leads to the adjacent Connector #103, pin #6, which is what I understand to be circuit #480.

Before I stab into this wire, let me just get a few things straight....

The red lead of my green LED will be hooked up to 12 volts. The black lead will be hooked up to this #480 VT/YL wire, which leads to the PCM. Now, doesn't the PCM generally operate with 5 volt signals? Based on my meter measurements above, and your knowlege of electronics, and your experience doing this, you are saying that the PCM, not the transmission, will NEVER see the 12 volts coming through the LED?

Forgive my thick headedness here, but for a lark, I hooked up the red lead of one LED to power, and the black lead of this LED to the red lead of another LED, and the black lead of that LED to ground. Needless to say, both LED's lit up in this "in-series" circuit. How is what I have just described different from hooking up the black lead to circuit #480, instead of another LED? Crewzer, you keep mentioning the harmlessness of LED's in parallel... I just keep tripping over a little cognitive dissonance wrapping my mind around this.

I'd say, when the PCM wants to ground circuit 480, what's this powered LED seeking a return to ground all of the sudden mean? When the PCM wants to keep #480 open, and the PCM operates with 5 volts... whats all this 12 volts potential in the circuit mean? Or is it really just the 1.718 forward bias voltage let through? Oh boy...

As I stated and by my sig you can see that I really can't comment on an informed basis on the 5V question you have since I am designing something to operate with virtual hardware right now until I actually get my van Until my virtual hardware becomes real and I get a set of shop manuals and wiring diagrams I am more ignorant than most. However, as I understand it in general, 5V is a typical level for activating/powering solid state devices such as ICs, transistors, etc. were the currents are on the order of a couple hundred microamps up to several milliamaps. As I understand Crewzer mention of the ground wire being part of a circuit that draws 300ma or more doesn't sound like a 5V circuit, but again I'll let others give a more definitive and informed answer on this.

Can't help with all them wires and connectors since mine are all lost in virtual space but rest assured I will be closely watching what others say about all them wires and connectors that I currently can't see and am sure the answers you get will help me greatly when I try and get up the courage to "stab" into that wire.

When you hooked up the two LED's in series and they both worked is essentially the same theory I orginally expressed about using the largest resistor that will allow the LED to operate to your satisfaction. I always follow the axiom that when powering such indicator/sensor circuits the more resistance (i.e. the less current thru the circuit) the better. You could with your single LED try one with an additional say 1K ohm resistor and see if the LED brightness is acceptable, this would be close to putting the two LED's in series.

Don't feel bad about being let out of school they did let me out and am constantly amazed at how much I thought I knew turns into what little I really know now.

Glad you got those "cobwebs" out of your electron detector. They have a hard time seeing those little bitty "things" when they are vision impaired by such things as "cobwebs".

My motto "Knowledge is Power"

OK, let's see where we are...

The PCM runs off the nominal 12 volts; I'm not sure where the 5V question came from.

The PCM connection to the TCC solenoid coil is referred to an "open collector" architecture. It'll be the collector of an NPN transistor (careful, now guys, don't get too excited with this kinky stuff), and it's designed specifically to interface to circuits such as this. It's OK; really .

When the TCC is OFF, the voltage at PCM pin 54 will read around 13 volts. That's normal, since the current flow through the solenoid coil while measuring the voltage is so small that there's virtually no voltage drop.

When the TCC solenoid is ON, the voltage at pin 54 will be around 0.2 volts, which is typical for the emitter-to-collector voltage drop for transistors in a saturated state (in other words, turned on ).

I picked up a green 12V LED from my local RS this evening (p/n 276-271A). The red wire does indeed connect to +12 and the black to ground. This LED appears to be a good compromise: not too bright for driving at night, but bright enough to see during the day. From an electrical perspective, I wouldn't hesitate for a second to install this device into my own truck.

The red wire should be connected to (switched) +12, and the black wire should be connected to circuit 480 (VT/YE, or purple/yellow). Since the TCC solenoid coil is also connected to +12 on one side (via C1048 pin 12, circuit 391, red/yellow wire), and to circuit 480 on the other side, this will place the LED in parallel with the TCC solenoid coil.

NOTE: Thus wired, the LED will be in parallel to the TCC solenoid coil, NOT in series.

When PCM pin 54 turns "ON" (pull to ground), this will both complete the DC circuit through the TCC solenoid coil, thus activating the solenoid, and also completing the DC circuit through the LED (and resistor), thus turning it ON.

This will do it. You may need to carefully check the wiring color codes for C103. I see VT/OR (purple/orange) in addition to VT/YE (purple/yellow), so, if there's not not much obvious color difference between the yellow and orange tracers, perhap this is the mysterious "second" purple/yellow mentioned by Robyn.

A few more Ford clarifications/questions:

quote:

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Originally posted by crewzer:
The PCM runs off the nominal 12 volts; I'm not sure where the 5V question came from.

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The question came from the Ford Service manual...

"Vehicle Reference Voltage"

"The Vehicle Reference Voltage (VREF) is a positive voltage (about 5.0 volts) that is output by the PCM."

This may not or may not be relevant. I just want to make certain that the neither the PCM or the TCM ever "sees" the 12 volts supplied to the LED. If the LED is a reliable diode, I guess/hope that the 12 volts to the LED will not be detected, even during KOEO/KOER self-diagnostics routines or technician scanning. But if the LED is like most other things that I have purchased from Radio SHACK over the years, well... walk me through what would happen then?

quote:

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Originally posted by crewzer:
When the TCC is OFF, the voltage at PCM pin 54 will read around 13 volts.

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I hate to ask this, but how do you know? Is this something you were able to confirm with a meter, or is it a value published in a service manual?

Believe me, I don't mean that question sarcastically in anyway, so please don't take offence. I am just trying to reconcile the many "references" I have read on 5 volt reference voltage on most I/O signals to the PCM in Ford's PCED manual.

quote:

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Originally posted by crewzer:
When the TCC solenoid is ON, the voltage at pin 54 will be around 0.2 volts

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Same question, more or less. My first instinct is to try and measure it myself, but to do that seems to require stabbing into that wire again, or the removal of a connector which might disable other circuits required to get a valid "real world" result.

quote:

---

Originally posted by crewzer:
You may need to carefully check the wiring color codes for C103. I see VT/OR (purple/orange) in addition to VT/YE (purple/yellow), so, if there's not not much obvious color difference between the yellow and orange tracers, perhap this is the mysterious "second" purple/yellow mentioned by Robyn.

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Nope. No mystery about it. As I mentioned before, there is indeed a second, and a third VT/YE (purple/YELLOW) wires running in the same wire harnesses (12A581 and 15525). Those wires, Circuit #771 and Circuit #870, do not connect through connector C103, but rather through the adjacent parallel connector C1044. Yet these purple and yellow wires thread through the same harness that runs above the fuel pump as Circuit #480, which is why I posted the caution. That Roger grabbed the right one the first time is the mystery to me!

By the way, I changed my mind about using connector 103 as a splice point anyway. Too obvious to any casual technican that some type of wire splicing has taken place, and the connectors are not as easily opened by me as other Ford Wedgelock connectors. I was recently reminded that I have a Banks Transcommand, which interfaces with Ford wiring the same way I always like to, through sealed connectors with Wedgelock Pins, just like original equipment. This is a system that makes restoration to factory wiring absolute. There is an empty pin in the Banks connector, so one can remove pin 4 from C1048, insert it into the Banks connector. On the other end of the Banks connector, on can install a "Y" with one leg equipped with the same type pin terminal restored back into pin 4 of C1048, and the other end leading on up to the green LED.

That is, if everyone still maintains that it is a good idea to install this LED.

I'm all ears and learning a lot

While slightly off topic and for my info can you connect the proverbial where the "thigh bone" is connected to for this PIN 54 if it's readily available. From your description, I envision PIN 54 is the collector, emitter is ground, base is whatever + voltage that turns transistor on. Up until now I thought PIN 54 was grounded like a relay would and did not consider it the result of a transistor. If this is the case I can see why you have major concerns in simply grounding PIN 54 to manually energize the TCC solenoid. It unaturally creates an Collector to Emitter short and while might well energize the TCC solenoid, I have no idea what else it might do, or be capable of doing if the PCM decides to do something else

ALL EARS AND LISTENING CAREFULLY

Most sensors that are sending information TO the processor operate on 5V. All actuators, things that make something happen, operate on 12V. The TCC solenoid is an actuator and operates on 12V.

The solenoid always has 12V on one side. The wire that we have been discussing in this thread is the ground side of the solenoid. The processor connects this wire to ground to turn on the lockup clutch. When this wire is not connected to ground it will read about 12V because the voltage will travel through the solenoid to the wire, which is "floating." When the PCM grounds it, it will read 0V to ground.

The newer models use a pulse width modulated (PWM) solenoid. Older models used an on/off solenoid. For this use there really isn't much difference. With the PWM solenoid the LED will probably flicker before coming on bright. With the on/off it will just come on bright.

quote:

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Originally posted by Mark Kovalsky:
There are both 5V and 12V signals to and from the processor. Most sensors that are sending information TO the processor operate on 5V. All actuators, things that make something happen, operate on 12V. The TCC solenoid is an actuator and operates on 12V.

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THANK YOU! That clarifies that question immensely.

quote:

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Originally posted by Mark Kovalsky:
The only potential downside that I can think of is that there is an electrical circuit check in the PCM. It *MIGHT* be sensitive enough to detect the addition of the LED. If it does you will get the O/D light flashing and maybe the check engine light on. If this happens you may also go into failsafe mode, with the harsh shifts and maximum transmission pressures.

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YES, this is what I was worried about when I said "KOEO/KOER self diagnsotics test." I just didn't know quite how to put it. In fact this is what I have been worried about the whole time, as there are members here who have reported the TCIL flashing after they installed a TCC override switch. I read of them in my search, but no follow through on how the concern was resolved was posted.

Yet, Roger has installed and run both the LED light and the TCC switch with impunity! (I keep talking about you Roger, jump in here anytime ) Is it the "only two little wire strand" connection trick?

KEY QUESTION:
What can be added or subtracted to the LED indicator circuit to make it less detectable by the PCM?

A tochluodiodemitterNTVothaleneresistoid device, perhaps? Just Teasing there, Jim and Larry! I'm just jealous that I never got a piece of that E=IR pie when they were stacked high at the brain bake sale.

Gents,

Without having studied the schematics, I’d wager the PCM’s VREF of +5VDC is supplied to various sensitive sensors (i.e., the MAP and the TPS) as a fixed reference voltage rather than using the variable battery or alternator voltage for a reference.

It’s not relevant to this exercise. And that’s a good thing, because it means the PCM “outputs” are designed to deal with a relatively wide, or course, range of operating voltages and currents, and that’s part of what helps make this exercise to be of such low risk.

To be straightforward, the PCM will indeed “see” the +12 supplied to the LED, but only in the sense that it will have to sink the ~15mA pushed by the +12V through the LED & resistor at the same time that it’s sinking the current pushed by the same +12V through the TCC solenoid coil. This additional current is relatively small (probably less than 5% of the TCC solenoid coil current) and is no doubt well within the design range for the PCM. In other words, the TCC solenoid coil current varies from a bit from vehicle to vehicle, and even within vehicles, depending on the state of the electrical system. My view is that the PCM will never know the LED is there, and it won’t be detected except by visual inspection.

As for RS reliability… oh well … the good news is that if the LED fails, it will fail “open”, and the PCM will treat it as if it’s not even there. Even if it failed “closed”, a highly, HIGHLY unlikely scenario, the resistor would limit the amount of current through this add-on circuit to about 20mA, which, when added to the TCC solenoid coil current alone, is still well within the PCM’s capability.

OK, now on the voltages at pin 54.

With pin 54 turned OFF, there will be virtually no current flowing through the LED/resistor and (parallel) TCC solenoid coil circuit. Although these devices do have resistance, Ohm’s Law tells us that the voltage drop through them will be V=I*R. For a very, very small I (current), there will be virtually no voltage drop, so the measurement will be close to the source voltage. If the vehicle source voltage is 13V, the pin 54 OFF voltage will be around 13V (as note by Mark, "float").

Another way to look at this is to treat it as a voltage divider. Since the coil is a relatively low resistance, and the OFF output transistor a relatively high resistance, there will be little voltage drop across the coil and we’ll see most of the voltage difference across the transistor.

When pin 54 is turned ON, the output transistor’s base current should be enough to drive it into a saturated state. The typical collector-to-emitter voltage drop for a saturated switching transistor is ~0.2V, so, with the emitter tied to ground, the output (pin 54) should be in the 0.2 to 0.3 V range. (This, phenomena, BTW, is why transistors, even saturated ones, get hot. Since P = I*E, the power dissipated by the transistor is equal to it’s saturation voltage times the current flowing it.)

Quote: There is an empty pin in the Banks connector, so one can remove pin 4 from C1048, insert it into the Banks connector. On the other end of the Banks connector, on can install a "Y" with one leg equipped with the same type pin terminal restored back into pin 4 of C1048, and the other end leading on up to the green LED.

This sounds like it will work as well as minimize visual detection. The black lead from the LED/resistor should be connected here, and the red lead to (switched) +12.

Is this whole thing a good idea? I think so. One of the keys to automatic transmission longevity is to keep it cool, and locking the TCC whenever possible is a vital part of that strategy. The indicator will allow users to experiment with different driving techniques and gear selection (i.e. OD “ON” or “OFF”) and learn more about how and when the TCC will lock, especially when towing.

Did you ever get your light installed? I am planning on installing mine tomorrow.

quote:

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Originally posted by campster:
Wow--quite a stir over a little LED

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You should see me at the grocery line, trying to decide between paper or plastic...

Happily, I finally have it installed. Haven't turned the key yet...

While installing the light, I thought I would open all four doors, rotate the truck upside down, and shake out all of its' interior contents... so out went the dash fascia, glove box, passenger air bag bezel, door panels, you know... the usual stuff that people who over-extend themselves do when they are just out there to change a light bulb! If you were to ask me to plant a garden, and pointed to two patches of ground - one being rich, dark, crumbly loam... and the other a cold slab of granite - guess where I would first strike my hoe? Yep, and you would hear the ringing of that metal pounding the rock until kingdom come, because by gum, that's where I started.

Campster - I second that "Stir comment" over this little LED, but IMHO having read numerous threads about this mod, this one has more information in one place about what is actually going on than a lot of others which can't really hurt.

Robyn - Did you experience the same thing as PSDHokie concerning the flickering? Also what year is your vehicle? BTW - by the time this thread is finished its too bad it couldn't be retitled - "everything or almost everything you could ever want to know about the TCC LED converter indicator"

STILL ALL EARS AND LISTENING CAREFULLY

quote:

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Originally posted by PSDHokie:
"when under operation the light just comes on... The light does not blink or flicker at all when this happens..."

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My light...(finally hooked up)... seems to gradually come on when the TCC engages... not just ding!, but more like dddiiiiiiiiiinnnnnnggggggg up to full brightness. (descriptive adjectives, eh? just when you thought i was a little dingy, i go and prove it) I am not seeing a flicker, but a gradual increase in brightness during the engagement.

However, when my torque converter disengages, the light extinguishes right now. Poof!

quote:

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Originally posted by PSDHokie:
"...under normal driving it will lock up around 55mph and unlock when I hit the brakes or at 38mph. Under hard acceleration it will lock up around 25mph or so."

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Quite a difference from my truck. My TC regularly locks up at speeds well below 55mph. Mine locks at more like 25 mph, but no "hard acceleration" is necessary. Just poking aimlessly along and the TC locks.

I looked in the service CD but the schematic print is not legible enough to read nor can I find the specific locations of the termination points. I can see the four connectors on the fender well but from there it goes into the worst amateur looking rats nest I have ever seen on a vehicle. Where is pin 54 located and is it accessible on the PCM?

I found a foot switch at Radio Shack for 5.00 that was designed for tape deck and dictation machines. It looks like just the ticket for manual control of the TCC. Mounted on the firewall just above the carpet, it will be out of the way yet still comfortably accessible.

"where to find SXL?"

Yeah, right. Good luck! Here we have an automotive wire standard, set by the Society of Automotive Engineers, (SAE J-1128), which specifies a wire jacketing material to be made of cross-linked polyethylene, (the cross-linking being the KEY, signified in the wire code by the "XL", polyolefin can also be used, as long as it is cross-linked), meeting a temperature requirement of 125 degrees C, stranding to be a minimum of 19, and not one...

not one...

NOT ONE...

so called "auto" parts store carries this wire. Name the store... Pep Boys, Auto Zone, Kragen, Checker, CarQuest, GrandAuto, Napa, Superior, Performance Plus, and the list goes on... not one stocks this wire, the same grade wire that is standard equipment on Ford vehicles today. Chrysler vehicles have a seperate but equal standard, I think off the top of my head it is SAE-J1156, but no matter, it can't be had at an automotive parts store.

Even Banks ships fancy looking double jacketed but inappropriate wire with their guages... stamped "Oil and Gasoline resistant" and "rated to 600 volts." So what? That is still not OEM AUTOMOTIVE class wire. It is household or industrial wire. It does not have the strand count for flexibility in a constantly mobile environment. It does not have the heat resistant crosslinked jacketing to withstand underbody and underhood temperature constants.

Sorry to go on about this, but I have conducted numerous tests on wire jacketing materials, applying both internally conducted heat (overcurrent) and externally applied heat (radiant), and the performance of SXL wire jacketing over the TFFN or the AWM or the MTW standards is palpable. You can see and feel that difference. You can watch one wire jacket literally cook, flame, smoke, bubble, drip off, seperate, whatever, while the SXL, under the same conditions, maybe will become slightly discolored.

When an SXL wire ever does cook within a bundle of wires, it does not effect the other wires in the harness. There is less chance of a melted glob of insulation ruining the neighboring wires. One can withdraw an SXL wire from the harness, whereas a group of PVC jacketed wires will be melted en masse.

Feel the texture of the OEM wires in the truck, and then feel the wires that aftermarket vendors sent to install their accessories. That difference is engineering experience. That experience is expensive. I have to pony up a $100.00 minimum order everytime I get a hankering to use the XL class of wire that Ford recommends in underbody and engine compartment applications. And the OEM supplier I get it from is doing me a favor at that.

I'd love to be able to go down to the store and buy the right kind of wire in the guage and color I choose. But consumers who don't know the difference won't pay the difference, so the stores won't stock it. I seriously doubt you will find it, without special ordering it.

1) Throttle Body Injection Socket (Direct
Ignition) GM, Conduct #85138, Pep Boys,
$9.99 (NAPA has them for $15.00. Part
#2-18462)
Application: Plugs into the EBV connector
under & behind the turbo.

2) Spader Pin to Coil Harness Adapter, GM,
Conduct #85197, Pep Boys, $14.99 (ouch)
Application: Plugs into the OEM EPV
connector with the spring clip. Note:
This is not an exact
match. the pins must be bent in slightly
to mate with the OEM plug. The overall
fit is good and waterproof.

3) Bosch Fuel Injector Repair Socket,
Conduct #85850, Pep Boys, $5.99,
Application: Connects to pressure switch
on the master cylinder for cruise control
cancel.

This was my major snag. Hopefully now it won't be yours. While at Pep Boys, they have a good assortment of insulated male/female disconnects. A pack of 5 each @ $1.99.

I don't work for them. It's just nice to get everything at one store.

For the T/C lockup, I used the green LED, and the red led for the ESOF dissable indicator. I removed the ESOF switch and installed the leds in the bottom corners. T/C on left, ESOF dissable on the right. Drilled and installed a cool looking spdt paddle switch that I found at Rat Shack.
I cut the red wire at the vacume solinoid and ran it to the switch center pole. One of the others goes back to the solinoid, and the other to the led. When the switch is down, the circuit is normal. Flip it and the citcuit is diverted to the led.
At first I had the led hooked up assuming that the solinoid wire is hot when activated. No light! Then I got to thinking that maybe is is a ground like the T/C wire. Sure nuf! I reversed the led and ran the wire to my switched hot. BAMMO! This is cool!

quote:

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Originally posted by DZacc:
ESOF disable? Is this for backing in low range?

I promised myself I would finish the other 3 projects before starting another one.

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Backing, pulling, whatever. Just be carefull, that is alot of torque back there!

Hi Guys:
I did most of this stuff, LED for converter lock/unlock info, manual converter lock and 4x2Low feature last year and just wanted to pass on to you that everything has worked well with no problems.

Working on a "Cab Control" for rear axle Air Lifts and 5er Pin Air Box Control now. The heat and humitity were having here in Kansas City is makeing it hard to even move around though.

When you use the exhaust brake with the torque converter unlocked, the end result will be lousy braking and very high tranny temps. With the TC locked it will act more like a manual transmission.

For us with the 2001 model the TC slips way too much during normal driving. I want the ability to manually lock the TC instead of the truck downshifting and slipping the TC at 2800 rpm until it's ready to shift back up. Sometimes it does this with no real increase in speed.

This is what I came up with, but it's just on paper at this time.
http://forums.thedieselstop.com/cgi-bin/ubbcgi/ultimatebb.cgi?ubb=get_topic&f=25&t=002705&p=

quote:

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Originally posted by Rich D:
my TC locked LED now blinks,or should I say flickers, twice real fast right after I turn the key to start the truck.

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I put a switch on the TC too. I love it. On the back roads I turn O.D. off and lock the TC. It's like driving a standard. I can lug it down on a corner or a hill. Everytime I hit a circumstance where I know it would have downshifted and upshifted, I have a big on my face.

The O.D. light on the shifter flashing, (error code) is the only draw back. But it's a small price to pay for the extra fuel mileage and less wear-tear on the Tranny and Drive Train.

that's exactly the way I use it!

works great slowing for corners that are right before a decent incline (at neighborhood speeds)

ain't this site great!!

Now I have some questions for midman, the Dave, et al, who have added the switch:

How do you know what's happening down there? (as far as "less wear and tear" on the transmission)

How do you know when you should release the switch?

What is the slowest speed or lowest rpm that you have driven with the TCC overide engaged?

By ignoring the flashing TCIL light, how will you know when you've gone too low before the cumulative damage you may have done suddenly reveals itself?

How do you know whether or not the transmission computer is switching into self-protection mode (altering EPC parameters) once it sees a failure of the TCC to release?

I guess I would need to know a lot more about transmissions before trying to out-smart the transmission computer, or out-think the engineers who programmed it. Not saying that this isn't possible... especially among some of the members of this site.

quote:

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Originally posted by Robyn:
This thread transformed from a TCC indicator LED light to a TCC interrupt switch. I only added the LED light... as that was all the courage I could summon up.

Now I have some questions for midman, the Dave, et al, who have added the switch:

How do you know what's happening down there? (as far as "less wear and tear" on the transmission)

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Well, I'm certainly no mechanic...but from what I've learned here; having the TC lock-ed up as early as possible will lower the ATF temp. lower temp means less wear (from beter heat dissipation, etc...)

also, I was wasting power and economy whenever the TC would unlock when I didn't need it too. (see example in my previous post)

quote:

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How do you know when you should release the switch?

What is the slowest speed or lowest rpm that you have driven with the TCC overide engaged?

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I release the switch when I feel the engine lugging. depending on grade, I will leave it locked down to 20-25mph...on level ground much lower. If I'm slowing to let someone turn off of the road, and I know that I'll be back up to speed immediately, then I'll let it stay locked- coast while they turn they get back in the throttle...keeps from simply spinning in the fluid wating the power.

quote:

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By ignoring the flashing TCIL light, how will you know when you've gone too low before the cumulative damage you may have done suddenly reveals itself?

How do you know whether or not the transmission computer is switching into self-protection mode (altering EPC parameters) once it sees a failure of the TCC to release?

I guess I would need to know a lot more about transmissions before trying to out-smart the transmission computer, or out-think the engineers who programmed it. Not saying that this isn't possible... especially among some of the members of this site.

A TC override switch in the hands of the ignorant masses (of which I am one) might spell disaster. But in the hands of the select and experienced few... well, please help me graduate to that group. HOW?

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My feeling is that with my upgrades creating more power, that tranny failure might be inevitable...so I'm either accelerating the process by playing with the PCM, or maybe the opposite...

The PCM was obviously programmed for the "masses". Most consumers want a true slushbox...nice easy shifts, etc...

My feeling is that anyone that knows how to drive a manual trans, can easily handle the few intricasies required to use a TC lockup switch.

I mean, the fewer times the tranny is hunting for a gear, jumping in and out of OD, locking and unlocking the TC>>>the more heat, wear and tear is occurring to all of the parts in there.

If I can control anything to lessen the hunting, the heat, etc... I will.

Maybe this tranny will hold up to massive hp/tq with my rudimentary mods...maybe not.

it's only money, right...

You just need to get some BALLS. Or get a relative that works for Ford and fixes anything you mess up.

Just kidding. LOL

Things I have tried -

1: Lock up Converter While sitting at a stop, idling. = Stalled Engine. Heheheheheeee

2: Lock up converter while accelerating, (not at a stop). = Not good, Clunks too much when it shifts to 2nd and 3rd Gear. You should be in 3rd Gear.

3: Come to a stop with Converter still locked = Engine Stalls See 1:

4: Lock up Brakes at 40mph while traveling down a hill with the Exhaust Brake on and TC Locked, (When a guy runs out in front of you to stop you from hitting his Dog that's running out in front of you) = Stalled Engine. See 3: Good for getting sympathy. The guy and everyone watching felt really bad after hearing that mighty Stroke go from a loud, hissing King Cobra to a Clattering, Pig Squealing halt.
This happened about 2 hours ago.

5: Go down the road, once Tranny shifts into 3rd, lock Converter and for miles and miles.

6: Come to a hill or a corner with Converter locked, (knowing the TC would have unlocked and Tranny would have downshifted to 2nd) feel the Torque kick in as you re-gain your speed and some more.

7: Kids, Please don't try this one at home - Sit at a Stop, Mash the Throttle and immediately lock the TC at the same time = Stalled Engine See 1: Don't repeat.

8: Sit at a Stop, Mash the Throttle, When Boost Gauge hits 10psi, Lock the TC = Big Grin, A little Tire Squeal, and a whole lot of ****'n and gett'n goin on.

One added benefit of the switch is that my Tranny does NOT like to downshift lower than 3rd gear when it is locked. I can take a 90 degree turn on to a side street in 3rd gear with the TC locked, (provided I don't come near a stop). As long as I am doing 20 or more mph, the Truck behaves extremely well with the TC locked. It up shifts to 4th and downshifts to 3rd without any negative side effects. It really does add to the fun factor and providing you don't do any of the stupid things I do, you won't hurt it at all. I am sure it will improve mileage and decrease Tranny and TC wear.

If you have the $2.00 Exhaust Brake, This TC switch is a must. It absolutely makes the EB useable with the Auto. Especially cruising around the backstreets with O.D. off. I use it on all of the hills and corners. It was un-useable anywhere but on the Highway before.

If anyone is wondering what the LED's look like that Robyn provided Radio Shack numbers for earlier in this thread, This is what they look like.

For Sale - Y2K Ford PowerStroke. Diablo 130hp Extreme Chip, 5" Hypermax Exhaust, PowerShot 2000 100hp Propane Injection system. Never abused, Babied it's whole life. TC Switch not included. Does include 1 ZooDad Da'Man Ram Air, 1 Hissing Snake and 4 Squealing Pigs. Pigs might be up for Recall. Just kidding.

quote:

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Originally posted by The Dave:

ain't this site great!!

Dave

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It's the best.

Enlightening and entertaining answers, from both of you: The Dave and midmadn. An enjoyable read, to be sure! I'm still smiling midmadn!

The TCC indictor works great and it operation is very interesting. In my particular installation the total additional current draw on ckt 480 is 11 MA (i.e. the coil draw on the Radio Shack relay). I should be so lucky if my TC would lock/unlock around 40mph. In my case it locks at 44/45 and unlocks at around 40mph and will only lock up in OD. Take it out of overdrive and the TC automatically unlocks and remains unlock regardless of engine rpm or vehicle speed. It would really be nice to be able have the TC locked if you hit the overdrive off button and are in third gear above about 30mph when going up or down hills, expecially if you are towing. However, there may be reasons not readily understood by us why this is so and I'm not comfortable that if as Robyn has pointed out if you take over the trans PCM programming and manually lock the TC while the say trans is still shifting up or down doesn't put more stress on the TC clutch than it is designed for. I'm not a transmission engineer and until I understand much more on the design and operation of my 4R100 trans, I will wait on installing a manual TC lockup system.

Also the actual operation of the TCC is very interesting. My pilot lights comes on in distinct two stages, first dim and a second or two later full brightness. This might be due to the PWM modulation of the PCM signal driving the ckt 480 signal to ground in two stages the first which cycles the relay coil at to cause two distinct levels of brightness in my pilot light. The reed relay I used is called fast response and might be just be sensitive enought to see this PWM modulation variance. This operation is very consistent. Two brightness levels when the TC locks and simply off when it unlocks.

Thanks in advance for any help.

quote:

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Originally posted by Gary Kelley:
,I know that it is possible to have the TC unlock at a certain speed.Since I have wired mine, it stays locked till . . .>stop . . .Any ideas on how or where to wire it so that it might finally unlock at say 15 mph?

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Did you wire in a switch or an indicator light? Where and how did you wire it?

Given the exhaustive nature of all the posts in this thread that precede your message, it is difficult to imagine any more instructive advice to add.

When Ford reads posts like this, I'll bet they lump us all into that "Void That Warranty Pronto" book in the big blue oval sky. I guess that is why I like delving into painstaking detail, so that no mistake is made that gives some of our more useful and otherwise harmless modifications a bad name at the service department.

Too many people have gotten it right for you to have got it wrong, so you'll have to be more detailed as to what you did so the folks here can set you back on track.

And, just for laughs, re-read all three pages of this thread. Every circuit number, every connector number, every wire color, every LED part number, along with expected voltage, current, and resistance levels, have all been explored in this thread. If anything posted is confusing, I am certain the original poster would be willing to clarify.

Finally, I would be curious to know how you determined that 15 mph is an adequate road speed for your TC to disengage. The Ford stock programming calls for disengagement at around 37 mph. It is my understanding that there are certain immutable alterations in fluid dynamics that naturally occur in the rotating torque converter at speeds in the vicinity of 40 mph, give or take differences in gearing and engine rpm. It appears that this physics has a great deal to do with why our TC clutch is commanded to disengage at that time.