Iam looking for some help with a trailer wiring problem on my 2004 f-350. I have an enclosed car trailer, the other week when I went to unhook it after sitting over night, I heard a clicking noise which I found out was coming from the trailer brakes. When I unplugged the trailer from the truck it stopped. I took the truck to a trailer dealer and they pluged a tool into my trailer plug, and you could see that was a slight charge to the brake pin that would go on and off. They plugged a new brake control in and it did the same thing. I redid the wiring conections under the dash, and replaced the plug and wiring at the back of the truck and it still does it. I have a Prodigy brake controller on a 2004 Ford f-350. Thank you for any help with my problem!
Take a voltage check between the brake pin in the 7 wire receptacle on the back of the truck and your truck DC common (gnd.) Or if not meter then a 12 volt light bulb and 2 wires. Or plug in the trailer and listen for the clicking again. Not the best option but something better then nothing.
You should see the voltage pulsating.
Once it starts pulsing go under the dash and pull the power from the brake controller. Does it stop pulsing? If it does the brake controller is having issues or is being tricked to think you are standing on the brake pedal. If it keeps pulsing then the brake controller has nothing to do with it as you unhooked it.
If you made it to, it is beyond the brake controller then you have to trace the brake wire from in the cab all the way to the 7 wire receptacle in the back of the truck. Some how that wire is skinned and it is getting power from some other source.
Assuming the wire to the back is OK and that the problem stopped when you unplugged the brake control then a possible suspect is the brake pedal switch is malfunctioning and sending a signal when it is not suppose to be. If you can find the brake pedal switch, pull a wire off it and that will remove the brake switch from the equation.
If it is still pulsing with no brake switch connected, the controller plugged in, then something may be adding voltage to the wire from the brake pedal switch to the Prodigy tricking the prodigy you are stepping on the brake pedal.
You have to keep searching 1 wire at a time to eliminate what it is or is not. Eventually you have to find it as you already said you changed the controller with a new one and the problem was still there.
Hope this helps
* This post was
edited 07/19/12 09:26pm by JBarca *
John & Cindy
2005 Ford F350 Super Duty, 4x4; 6.8L V10 with 4.10
CC, SB, Lariat & FX4 package
21,000 GCWR, 11,000 GVWR
Ford Tow Command
1,700# Reese HP hitch & HP Dual Cam
2 1/2" Towbeast Receiver
2004 Sunline Solaris T310SR
(I wish we were camping!)