Right Side Turn Signal/Brake Light Function Not Working on Curt Wiring Harness 55242 on 2002 F-150

Question:

I installed the Curt wiring harness C55242 with ease on a 2002 F-150 Flareside with factory 4-flat connector. The problem is no power coming from the C55242 harness to the right blinker/brake light . All lights work on the truck. I used a check light and have running lights and left blinker/brake at vehicle end but no right blinker/brake. Have cleaned all ground connections and checked all fuses. This is not a trailer issue because I havent hooked the trailer to the truck. Any ideas

asked by: Roger G

Helpful Expert Reply:

It sounds like the problem you are having with Curt trailer wiring harness # C55242 on your 2002 Ford F-150 could be a few different things. First, you said you checked the fuses. But did you also check the relays? It is possible that on your truck there are relays used to control the trailer left and right run/brake light functions. You would use the owner's manual to find the locations.

If all the relays are good and in place, then it could be a wiring issue. If you unplug the Curt harness where it connects to the vehicle and then test the vehicle end plug with a circuit tester such as # PTW2993 that should tell you if the factory harness has power.

If it doesn't have power, then there is a wiring issue somewhere between that factory connector and where it terminates at the front of the truck. If it does have power, then plug the Curt harness back in and test the green wire at the back of the 7-Way. If there is no power, there then make sure the white ground wire is attached to a bare metal surface and test again. If there still is no power, then there is something wrong with the harness and it will need to be replaced.

expert reply by: Michael H