Troubleshooting Rear Parking Lights on 2011 Ford F-150  

Question:

Expert Reply:

The rear park lamp circuit in a 2015 Ford F-150 is protected by a 10A fuse in position 40, according to page 333 of the owner's manual. I suggest re-checking this one fuse position and trying a new fuse, just in case.

It sounds like you have issues with both your F-150's own lighting functions as well as those on its trailer connector. This tends to suggest that the place to troubleshoot is the OEM wiring connection under the truck where items like 7-way # 118283 and 4-pole # C56110 plug in. Both use the same rectangular connector shown in the photo.

You can use a circuit tester like # PTW2992 to probe the contacts on that OEM connector to see if signals are present. You can also test the bulb sockets at the parking lights to make sure power is reaching them. If there is corrosion in the sockets you might try a bristle bush like # DW00254.

You can also check your main wiring harness ground connection at the truck frame to make sure that ground is made to a clean bare metal surface that is free of rust, grease and paint. A weak main wiring harness ground can cause a lot off issues with lighting functions, especially those that use the circuit for parking lights.

I suggest removing the main harness ground ring terminal and sanding off that point to expose clean bare metal. Then apply protective dielectric grease # 11755 and re-attach the ground terminal. Often this step will correct issue with the running light/clearance light circuit.

expert reply by: Adam R

0

click to enlarge