This past weekend I loaded up my 3 horses on my trailer and found out going down a hill that my trailer brakes aren't coming on and tracked this down to a problem with the truck. need possible ideas for troubleshooting this before taking it to a dealer to check wiring problems for shorts somewhere.


What doesn't work: trailer brakes not getting any power to the brakes. When I first pulled out the truck had error message popping up saying Trailer wiring fault and once in a while that would disappear then come back on and once or twice went to Trailer disconnected. My friends hooked up my trailer to their truck and the brakes worked on the trailer.


What's working: turn signals and brake lights coming on in the trailer.


What we checked so far: fuses, sprayed truck plug with wd40 on the pins. The brake pedal not activating the brakes and tried just the slider bar on the ford integrated brake control box.


Background: brakes were working fine back in October. December hauled them a short distance and didn't notice any braking problem but road was mainly flat and when coming down a small grade they seemed fine but I was going slow also. Back in January, I took the truck to a Firestone to get general maintenance work done on it including truck brakes checked for wear and tear and they had to replace the truck battery.


Where does the truck ground wire go to in the truck to ground it out? All that I can find is that it has to go to some pure metal, no painted surface but can't find anywhere on where to check this out on the truck to see if it is still making contact. Could the guys at Firestone have not hooked something back up or knocked it. The last thing that I would like to look at before getting the wires all tested.


I have a 2008 F250, gas

 

A few things you can check:
On our Fords, the blue wire is for brakes and the white wire is the ground.


1. With regards to the trailer connector under your rear bumper, check voltage to the pin for the blue wire with somebody applying the brakes for you.
2. If that checks out, check for continuity to make sure its able to go to ground.
3. Check the power supply going into the controller under your dash and check to make sure that the blue wire coming out of the controller has voltage when the brake pedal is pressed.

 

Check trailer ground first. That is the usual suspect when dealing with trailer brake issues.