No Trailer Lights On Ford F-150 Until Brake Pedal Is Applied

Question:

The trailer lights were not working at all then i replaced a blown fuse and now they will only come on when i hit the brake but they stay on for a few minutes then turn off. neither turn signals work...

asked by: Jason D

Expert Reply:

If none of the trailer lights are working then that means you have a ground issue, severed trailer wiring harness, or there is an issue with the vehicle's computer. The first step would be to test the trailer connector on the truck to see if you are getting power here. If no power is here then check the ground for the trailer connector and or trace some of the wires back while checking for breaks. If there is power on the trailer connector then do the same for the trailer side as well, check the ground and trace back wires.

I have attached a trailer wring help article with troubleshooting tips as well. If you can provide a bit more detail on what exact circuits are not working and what you have done to troubleshoot this so far I may have more exact advice to provide but it might just be best to take the vehicle in for service as well.

expert reply by: Conner L