I'm thinking to add a switch to power up the trailer brakes for parking/ loading/ emergency, etc. I would think I need a diode in line to keep the power from feeding back to the controller (Prodigy). Has anyone done this?
I see the Brakesmart has this feature built in, but I'm not sure if I should spring for the $435. I do get irritated with the prodigy, as it doesn't put on full power when I think it should. so someone could talk me into it maybe. [img]/ubbthreads/images/graemlins/smirk.gif[/img]
If you're talking about an RV trailer with electric brakes, then you probably already have it. It's that little widget that has a cable coming out of it that must be tied down to something in the bed - so in case the trailer gets loose from the tow vehicle the trailer brakes will automagically lock. You can jerk on that cable and pull out the key, which should lock the trailer brakes.
That system assumes you have a battery in the trailer to power the brakes. And the brakes will unlock if the battery runs down. So it's not a good idea to use it for long-term parking. But it should work just fine for short-term parking/loading/emergency. That's why it's required to be on all trailers that have electric brakes. [img]/ubbthreads/images/graemlins/warmsmile.gif[/img]
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My Sierra Blanca is a '99.5 PSD CrewCab hot-rod Towing Machine! BTS tranny; TurboRamAir intake and 4" stainless turbo-back exhaust; DP-Tuner tunes flashed into an Edge Evolution tuner; ISSPRO EV gauges and TTM; AIC; SP-Diesel exhaust brake and torque converter controller. I special-ordered it new and plan to drive it until it quits.
A word of caution in using the "break-away cable" ...
Activating this cable while your trailer/truck electrical plug is still connected can and sometimes does fry your brake controller by backfeeding 12 volts to the controller. Some controller instruction manuals caution against this. Some brands are immune and are not damaged (they probably have a diode). Also pulling the cable and using it as a parking brake sends full power to the brakes from the on-board batteries. Doing this for extended times could melt brake wires and or burn out the brake magnets. Electric trailer brake components are not designed to take full power for extended amounts of time.
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2002 F350 4x4 CC DRW Lariat 7.3 auto 4.10 LS diff.(bought 5-05 @ 76,000 miles) Pyro, Boost, and Trans gauges. AIH delete. Tru-Cool Max trans cooler. Magnafine filter. Royal Purple MAX synthetic ATF. 55 gallon aux bed tank. 2LO Mod.
I don't know about the effects of applying 12 volts for more then a few seconds to the breaks. I have used the break away on my 5th wheel once to hook up under some pretty unusual conditions. It was on for about 2 minutes and seems to work fine now.
As far as how to wire what your talking about it should be fairly easy to do. If you use a 3 pole switch the center pole can go to the trailer, one pole to the break controller and the other to the 12v power supply.
Normally the switch will connect the trailer with the break controller. When the switch is flipped it will disconnect the break controller and apply 12v to the trailer. No diodes or other fancy wiring required.
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Do electric trailer brakes work at all in reverse?
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<font color="green">They might be theoretically supposed to; but, I never had any that did.
Also, applying constant current, in an effort to hold electric brakes, will melt a lot of expensive stuff.
I have seen a few trailers that had standard parking-brake cables with a manual activated ratchet-handle on the trailer frame.
Pull the handle and the parking-brakes lock in the same manner that they do on a standard vehicle.
Of course, this must be applied/released from outside the tow-vehicle.
This is one more big advantage of Vacuum-over-Hydraulic brakes; they can be locked down indefinitely, while hooked to the vehicle, and for quite some time, while un-hooked.
It's on my gooseneck flat deck tilt. I had an experience the other day on a steep hill on a dirt road when loaded, couldn't get up it (shouldn't have tried, either) stopped halfway up, and started sliding down [img]/ubbthreads/images/graemlins/eek.gif[/img] any experienced trucker would know how much steering traction I had, but anyway, got it stopped, truck was a little sideways in the road. Put it in low range 4x4 low gear, and pulled it up the hill! [img]/ubbthreads/images/graemlins/biggrin.gif[/img] Needless to say my pulse was a bit elevated for a while [img]/ubbthreads/images/graemlins/biggrin.gif[/img].
Anyway, I know I could have grabbed the brake controller handle, but my hands were kind of full at the time. And yes, these brakes do work in reverse. Of course, the prodigy isn't going to put much current to the brakes as there isn't much deceleration going on. So, if I had a switch for such kind of situations (hopefully never again)also for loading/ unloading trailer, as the truck park brakes leave a little to be desired.
LongRider, you are right about the hyd brakes. I might look into switching the trailer over in the future.
Also learned to always call and ask for directions when making a delivery. There was a much better way to get to where I was going. GPS isn't perfect. [img]/ubbthreads/images/graemlins/phoney.gif[/img]
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I had an experience the other day on a steep hill on a dirt road when loaded, couldn't get up it (shouldn't have tried, either) stopped halfway up, and started sliding down [img]/ubbthreads/images/graemlins/eek.gif[/img] any experienced trucker would know how much steering traction I had,
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<font color="green">With a trailer, when you quit going up, you are gonna slide down--backwards--, fun, ain't it??
Being in the livestock business for many years, I have had my share of sliding back on bad hills, even on blacktop a few times.
When she stops sliding, the cattle start climbing over each other, shaking the trailer, and here we go again, usually at the cost of a rear-end, driveshaft, or something more expensive.
I have many times said, when someone claims that they had rather climb a bad hill, rather than go down a bad hill, that person has not yet had trouble climbing a bad hill with a trailer, or a bigger truck for that matter.
At least going down a bad hill, one can see where he is going and maybe steer a little bit. </font>
if you want a way to wire a stand-alone switch that doesn't backfeed into the controller, use a relay.
Wire a SPDT relay as follows:
[85] jumper together with terminal [87]
[86] connect to your chosen activation switch, then the other side of that switch goes to ground
[87] wire to a high-current capable + source (power feed to brake control would work)
[87a] cut output from brake control to trailer brakes and connect end that goes directly to controller here
[30] connect other end of cut wire (out to brakes)
Closing the switch will apply full battery voltage to trailer brakes AND isolate the controller from any backfeed.
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2003 F350 CC, Short, XLT Sport (leather), 7.3PSD, Auto, 4x4. Homemade Tymar, Blizzard 810 Power Plow
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I had an experience the other day on a steep hill on a dirt road when loaded, couldn't get up it (shouldn't have tried, either) stopped halfway up, and started sliding down [img]/ubbthreads/images/graemlins/eek.gif[/img] any experienced trucker would know how much steering traction I had,
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<font color="green">With a trailer, when you quit going up, you are gonna slide down--backwards--, fun, ain't it??
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yes they do, I had that expirance back when I was 16, I had to move a car from our house, into town. We have a steep, icy driveway, which the rwd car wouldn't make(shoulda been a sign...) so I was forced to load it down by the house.
I hit the hill in 4wd, 2nd gear, and went 3/4 of the way up, and then came back down, with all four tires spinning on the truck. I almost put the trailer through the house.. :O and ended up stuck bad enough that I needed to pull the works out with the plow truck..
Lesson learned..
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88' F-350 reg cab, SRW, 4x4.
7.3/ZF5, 4.10's and 33's, rear locker,
banks turbo, 3.5" straight pipe, pump maxed, and advanced 2 degrees.
89' F-150, 351, 435, dual T-cases, rear discs, front electric winch, PTO winch rear, OBA, 40's
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if you want a way to wire a stand-alone switch that doesn't backfeed into the controller, use a relay.
Wire a SPDT relay as follows:
[85] jumper together with terminal [87]
[86] connect to your chosen activation switch, then the other side of that switch goes to ground
[87] wire to a high-current capable + source (power feed to brake control would work)
[87a] cut output from brake control to trailer brakes and connect end that goes directly to controller here
[30] connect other end of cut wire (out to brakes)
Closing the switch will apply full battery voltage to trailer brakes AND isolate the controller from any backfeed.
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Yep, that's exactly what I was planning to do. [img]/ubbthreads/images/graemlins/warmsmile.gif[/img]
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I had an experience the other day on a steep hill on a dirt road when loaded, couldn't get up it (shouldn't have tried, either) stopped halfway up, and started sliding down [img]/ubbthreads/images/graemlins/eek.gif[/img] any experienced trucker would know how much steering traction I had,
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<font color="green">With a trailer, when you quit going up, you are gonna slide down--backwards--, fun, ain't it??
</font>
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yes they do, I had that expirance back when I was 16, I had to move a car from our house, into town. We have a steep, icy driveway, which the rwd car wouldn't make(shoulda been a sign...) so I was forced to load it down by the house.
I hit the hill in 4wd, 2nd gear, and went 3/4 of the way up, and then came back down, with all four tires spinning on the truck. I almost put the trailer through the house.. :O and ended up stuck bad enough that I needed to pull the works out with the plow truck..
Lesson learned..
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Now envision a $100,000 forage harvester on a gooseneck (about 39K gross) and you'll have an idea how I was feeling! [img]/ubbthreads/images/graemlins/biggrin.gif[/img]
Lesson definately learned!
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I'm thinking to add a switch to power up the trailer brakes for parking/ loading/ emergency, etc. I would think I need a diode in line to keep the power from feeding back to the controller (Prodigy). Has anyone done this?
I see the Brakesmart has this feature built in, but I'm not sure if I should spring for the $435. I do get irritated with the prodigy, as it doesn't put on full power when I think it should. so someone could talk me into it maybe. [img]/ubbthreads/images/graemlins/smirk.gif[/img]
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Keep on smiling. electric brakes are made to have a magnet stick to the drum when powered. and then it moves outward pulling the lever and aplying the brakes. so powering the magnet without the wheel turning it dont pull outward so no brakes. [img]/ubbthreads/images/graemlins/shrug.gif[/img]if the drum is turning backwards then the magnet goes inward and you guessed it no brakes again. the reason why a brakaway workes is because the wheel is turning forward. [img]/ubbthreads/images/graemlins/vulnerable.gif[/img]
They work some in reverse, but it may depend on the brand - the reason I know this, when you hook a 6 pin trailer wired "wrong" (with the brakes on the center pin) to a Dodge with a converter plug that's "right" (center pin-to-center pin) you effectively lock your brakes when you put it in reverse and your backup lights come on. And yes, it'll spin you out if the trailer's loaded. [img]/ubbthreads/images/graemlins/grin.gif[/img]
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They work some in reverse, but it may depend on the brand - the reason I know this, when you hook a 6 pin trailer wired "wrong" (with the brakes on the center pin) to a Dodge with a converter plug that's "right" (center pin-to-center pin) you effectively lock your brakes when you put it in reverse and your backup lights come on. And yes, it'll spin you out if the trailer's loaded. [img]/ubbthreads/images/graemlins/grin.gif[/img]
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Yes but the wheel must be turning and it only activates one shoe. and that is if the bar in the middle is hooked up right. [img]/ubbthreads/images/graemlins/shrug.gif[/img]
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