Troubleshooting Weak Trailer Wiring Where Lights are Really Dim

Question:

I’m at my whits end. One trailer light is dim and barely works, even after new lights and wiring, it’s the same issue. I’ve checked the truck pin with a tester and it works fine. I’ve even cleaned all ground areas with steel cleaning pads. Frustrated in Tennessee

asked by: Dale W

Expert Reply:

Really dim trailer lights indicates normally that the ground of the circuits is weak. I know you said you checked grounds but is the trailer maybe aluminum and the wiring of the lighting is trying to ground through aluminum? If so run the grounds all back to the main ground harness of the trailer connector. If you have another tow vehicle see if the problem persists on the trailer with a different vehicle. That will allow you to know if the problem is the trailer or vehicle.

expert reply by: Jameson C