Troubleshooting Ford Factory Trailer Brake Controller Issues

Question:

2006 F250 Ford with integrated trailer brake control. Manual operation sends voltage to the trailer brakes. Depress the brake pedal and a very small amount of voltage goes to the brakes but not enough to engage them. Ford installed a new controller and I still have the same problem. Tech spent 7 hours trouble shooting and finally replaced the brake transducer. Still no trailer brakes. Your thoughts please. Thank you

asked by: Steven L

Expert Reply:

It sounds like you are testing your brake controller output from your pedal when at a stop. If this is the case, you won't see much output because it is a proportional controller and the factory integrated brake controller isn't sensing movement so the deceleration from no movement is requiring hardly any output. Since you are getting the correct output when hitting the manual override, that isn't an issue.

The only other thing to check is the brake controller input from the brake light switch when you hit the brake pedal. This on aftermarket controllers is the red input wire, but on a factory controller may not be red. This should give you power when you hit the brake pedal and nothing when you do not. You can use a circuit tester like # PTW2993 to probe that wire for function or use a multimeter like # PT89ZR to determine Voltage. If that is working then when you are on the road, your brake controller should be working and yet may need to be adjusted for brake output.

Another thing to check is your trailer brake assemblies if the power at your 5 o'clock pin on your 7-way is 12V when hitting that manual override. The brake magnets may be bad or the brake assemblies may need the shoes adjusted. I've attached some articles to help.

expert reply by: Jason S