Troubleshooting Trailer Running Lights That Dont Work With Vehicle But Do With Friends Car

Question:

Hiinch I recently bought a new trailer, however when I connect it all lights function as they should except for the rear tail lights. The brake lights work but the rear tail lights do not shine. I connected it to a friends car and all lights including rear tail and clearance lights worked fine. Could this be a grounding issue on my car? Kind Regards

asked by: Ben

Expert Reply:

It can be a grounding issue on your car, but it may also be a grounding issue on your trailer. Your friend's car may have a greater output to the trailer that can make a bad trailer ground not appear to be an issue. I'd start with cleaning all your trailer grounds and make sure they are clear of rust, corrosion, and have a bare metal to metal contact.

If that doesn't solve your problem, then I would take a circuit tester like # PTW2993 and check the running light function on your trailer connector. It is possible you have a bad ground or a bad trailer running light fuse on your vehicle.

expert reply by: Jason S