Running Light and Reverse Light Circuit Not Active on Ford F-150

Question:

Brake and signal lights work, running lights dont and brakes lock up in reverse. While hooked up to f150 2007. But when hooked up to another vehicle, everything works fine. Boat trailer problems

asked by: Alan S

Expert Reply:

It sounds like you have narrowed down the issue to the truck considering you do not have the same issues when hooked up to another tow vehicle. The first thing you want to check is the ground on the 7-way of the truck to make sure it is properly grounded to a clean bare metal surface on the truck's frame.

I am assuming the actuator on the trailer has an electric lockout that allows you to back up with hydraulic brakes. For the electric lock out to function properly, you need a working center pin on the 7-way that is attached to the reverse light circuit of the Ford. You want to make sure you have 12 volts of power on the center pin of the 7-way when you put the vehicle in reverse. If the Ford has a factory 7-way you want to check the owner's manual for the location of any fuses/relays that may be tow wiring/ reverse light wiring related to make sure a fuse isn't blown or missing. Since both the running lights and reverse light circuit is giving you issues, its most likely a ground issue on the truck's 7-way.

You may also consider checking the pins carefully for rust or corrosion and sanding them if needed. You also want to check for bent pins which could cause issues like you are referring to.

Please let me know if you are not able to pin point the issue and I can assist you further.

expert reply by: Heather A