Troubleshooting Dim Trailer Running Lights

Updated 03/18/2015 | Published 03/17/2015

Question:

I have a little tent trailer all of the signals and brake lights work fine. But, when I turn on the running lights, the tail lights are very very dim. You can hardly see the light in the dark.

asked by: Max

Expert Reply:

This sounds like a ground issue. Ground problems normally show up when there is more draw on a system such as when you have the running lights on and then use another function like a turn signal or brake light.

Make sure that the vehicle side and trailer side connectors are clean and free of corrosion inside and out. The main connector grounds should be attached to clean and corrosion free bare metal surfaces. The light grounds should also be attached to clean and corrosion free bare metal surfaces. If there is anything between a light ground and the metal trailer frame or if the trailer has an aluminum frame, tilt bed, or folding tongue, any of these things can interrupt the ground. Running jumper wires from the light grounds to the main trailer connector ground can help.

expert reply by: Jameson C