Troubleshooting Dim Trailer Lights

Published 01/06/2022

Question:

cant figure out why the top lights are on only when the camper is not plugged in with the vehicle unplugged

asked by: JERRY O

Expert Reply:

One of the most common causes of dim lights, is a weak ground. If your ground is rusted or loose, that can affect how lights work on your trailer.

The best way to check for a weak ground, is to disconnect your trailer from the vehicle and apply 12 volts directly to the trailer connector. Then apply the negative terminal to the connector ground, and one by one check the pins by applying the positive terminal.

If after these checks, your lights are still dim, you'll need to focus on the trailer wiring. The ground is what you'll want to check, usually a white wire attached to the trailer's frame. Make sure it is not corroded or loose. If it is, you'll need to reground on a clean bare metal surface.

Finally, you can use a multimeter like # PT89ZR to check all your electrical connections.

expert reply by: Bryce D