Ford Brake Controller Output and Dexter Axles - Diesel Forum

PineKnot · 12-01-2007, 06:34 PM

I posed a question about my weak (I think) '05 factory controller in another thread and got several helpful replies. Which leads me to this: The maximum output voltage I can get from my controller is 5 volts. The Dexter service manual calls for a range of 2 to 12 volts for its electric axle brakes. No wonder a max setting of 10 on my controller gives okay normal braking but maybe not much more, and certainly nothing dramatic. Both my trailers are new, and presumably the brakes themselves are in good condition.
My question is, am I on the right track here to finding the problem? And if so, is there a fix for the low max voltage output? One poster suggested replacement with a '06 or later controller, but I'd obviously rather fix what I have if possible. Anyone been down this road? Thanks.

Albin · 12-01-2007, 10:50 PM

I don't know what the output in voltage is on my '06 controller, but I have two 5k lb Dexter axles and I can smoke the tires when towing my Toy if I set it too high and use the brakes hard.

Sounds like something's wrong with your controller.

Good luck.

Al

pball · 12-01-2007, 11:17 PM

One of the guys that worked for me had an 05. never had problems locking up the trailer brakes if set too high, on singe, double and triple axle trailers. I agree with Albin, sounds like your controller

hotrodracer · 12-01-2007, 11:28 PM

Read between the lines below, OK?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: PineKnot</div><div class="ubbcode-body"> The maximum output voltage I can get from my controller is 5 volts.

WHERE ARE YOU MEASURING THE VOLTAGE AT?
IS THE TRAILER CONNECTED WHEN YOU CHECK VOLTAGE?

The Dexter service manual calls for a range of 2 to 12 volts for its electric axle brakes. No wonder a max setting of 10 on my controller gives okay normal braking but maybe not much more, and certainly nothing dramatic.

THE MAX SETTING ON THE CONTROLLER IS NOT VOLTAGE, BUT A REPRESENTATIVE NUMBER OF POWER SUPPLIED

My question is, am I on the right track here to finding the problem? And if so, is there a fix for the low max voltage output?

FORD DEALERS (most?) HAVE A TRLR CONNECTOR PLUG THAT CHECKS VOLTAGE, ETC.

One poster suggested replacement with a '06 or later controller, but I'd obviously rather fix what I have if possible. Anyone been down this road?

NHTSA.com HAS A COMPLAINT AREA THAT HAS AT LEAST 7 COMPLAINTS FOR THE '05 F350 SUPER DUTY TRAILER BRAKE CONTROLLERS. SEEMS LIKE THAT THE 05 CONTROLLER DOES NOT PUT OUT ADEQUATE VOLTAGE BELOW 20/25 MPH. DEALERS REPORT THAT'S THE WAY FORD MADE THEM, THEY ARE TO MFG SPEC, NOTHING WE CAN DO ABOUT IT, ETC. KINDA LIKE 'TAKE IT OR LEAVE IT,' Si???

SUGGEST THAT YOU ALSO FILE A COMPLAINT WITH 'NHTSA' AS I AM ABOUT TO DO. "IF" ENOUGH OF US DO THEY MAY CALL FOR A RECALL/REPAIR/REPLACE DEAL WITH THE '06 CONTROLLER THAT YOU/ME/WE 05 OWNERS NEED. GO FOR IT!!!

Thanks. </div></div> YOUR WELCOME...

PineKnot · 12-02-2007, 09:12 AM

Thanks for the information. Of course I'm aware that the "10" setting on the controller panel does not represent voltage. If Dexter says their axles require 12 volts for max braking, one would think the controller should put out that much or very close to it at its max setting.
I checked the voltage at the output pin on the seven conductor truck plug with the manual controller lever fully applied and brake pedal hard down. Can't see where having the trailer hooked up would make any difference. Can see where the "under 25 mph" would in a big way.
Maybe switching to an '06 controller is the only practical way out. Sorry, I have no faith in waiting for the guvmint to do anything worthwhile.
Seems to me that with an empty trailer or a light load you should have way too much brake at the max controller setting. I'm worried about that inevitable maximum effort stop someday with a full load back there.
Has anyone ever fixed one of these '05's to work properly?

ritschner · 12-03-2007, 08:07 PM

If you are measuring the voltage while the truck is stationary you may only get 5-6 volts. On certain PCM programs the voltage drops off when the truck gets below a certain speed. The voltage needs to be checked at road speed. Even on newer trailers the brakes can be out of adjustment, especially after the linings seat up. The first step wpould be to check trailer brake adjustment. Then check voltage at speed.

**SteveRacer** · 12-04-2007, 05:40 AM

The braking power is a related to how much the magnet puck is attacted to the brake liner face, which depends on the electromagnetic force. However, the electromagnet force depends on several things, but voltage really isn't the key ... it's current.

Ampere's Law basically says Magnetic Force (B) = constant (Mu) X Number of coil wire turns (N) X Current(I) divided by size/diameter of Coil.

Voltage is really a secondary measurement and relates to the resistance of the circuit.

But the magnetic field strength depends totally on the number of electrons moving around the coil, i.e. the current.

The Ford integrated controller measures all sorts of things, and it wouldn't suprise me if it can't lock up the brakes below certain speeds. It's probably design, although I'm not claiming it's a good one.

I always liked the idea of an integrated brake controller, mostly for the looks, but after reading about this thing for a few years I think the premium aftermarket controllers work a lot better than the integrated Ford unit, even though they attach under the dash somewhere with some sheet metal screws and obviously don't appear very factory.

-steve

PineKnot · 12-04-2007, 08:59 AM

Thanks for the additional information. Some net research has indeed revealed that the under 25 mph voltage/braking power is reduced by design, so my stationary voltage check (5v) was probably about right. My rolling brake tests may well have been under that speed too.
I'll definitely check brake adjustment, and rig up a way to check voltage at speed.

Bob C. · 12-04-2007, 08:21 PM

You say the trailers are new, so that leads me to the following.
As previously mentioned, check the brake adjustment. The axle factory thinks the trailer builder will adjust the brakes. The builder thinks the dealer will adjust the brakes. The dealer probably didnt adjust the brakes. Since the brakes are not adjusted, they havent "bedded" in yet. So, adjust the brakes, then make several (20 or so) moderate stops to bed the linings in. If you still dont have good brakes, then start checking the electrical.

PineKnot · 12-05-2007, 12:05 AM

Great advice. Thanks to all. The brakes were indeed way off loose. Adjusted them this afternoon and it took a lot of turns to get them in on the equipment trailer. I'll road test tomorrow. We read and we learn. This is a great site and you all are generous with your experience. This beats hell out of feeling your way in the dark.