Trailer Brakes and Brake Controller Do Not Work with Brake Pedal on a 2013 Ford F-150 XLT

Updated 07/08/2013 | Published 07/04/2013

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Question:

Having an issue when I apply the truck brake, the P3 display remains at zero and the trailer brakes dont work but when i use the manual brake lever on the P3 the trailer brakes work. Im not sure what else to do or try at this point, any suggestions? Thanks!

asked by: Scott

Expert Reply:

When a brake controller works with the manual override but not with the brake pedal that indicates an issue with the stoplight input. It could be that the red wire is not attached in the right place, or it could be a blown stop light or CHMSL fuse. To check the fuses, use the trucks owner's manual and/or the power distribution box lid to find their locations.

To test the input on the red wire, use a circuit tester like # 40376 if you do not already have one. The red wire should show power when you step on the brake pedal. If it does but the display on the controller still reads zero and the trailer brakes are not working, then you can try adjusting the power output on the controller. If that does not fix the issue, then there is something wrong inside the controller and it will have to be replaced.

If there is no power on the red wire when you step on the brake pedal, and it is not a fuse then it could be that the red wire is not in the correct location. The red wire should be right next to the blue wire. If it is not in this location, then it needs to be placed there for the controller to work with the brake pedal.

expert reply by: Michael H