Troubleshooting Trailer Running Lights that Stopped Working on a 2006 F150 Brake and Turn Still Work

Question:

the running lights on my trailor stoped working the turn and brake lights still do i checked fuse 10 under the dash and it is ok and the wiring all looks good 2006 f150 trailor running lights

asked by: Eric

Expert Reply:

I would first check the trailer connectors for corrosion any moisture can get in there and cause the wiring to malfunction, if there is corrosion I recommend replacing the connector. I like the # HM48480 because it has a weatherproof, insulated lid that covers the terminals.

Also, check that the running light wire functions properly at the connector. If it does not work, then the wire is most likely broken or loose somewhere behind the plug. You will want to test the wire with a circuit tester like # PTW2993.

Since the harness # 118242 you referenced includes relays you may want to check these in addition to the fuse location R201, I've attached an image of where to locate this relay. The best way to test a relay is to replace it with a known working one.

If you continue to have issues, I would be more than happy to further troubleshoot this trailer lighting issue with you.

expert reply by: Jackie C