Troubleshooting Trailer Lights With Some Functions But Not All

Question:

When I turn on the blinker for the left side, both blinkers flash. If i turn on the right it works like it should. Further, the right side brake light does not come on but the left one does. Any ideas?

asked by: Stephen L

Expert Reply:

It sounds like you have a connection issue at the plug. I recommend cleaning the connections with some sand paper or steel wool and then using some dielectric grease like # 11755 to keep the connections clean and working properly. This should help with any connection issue coming from the vehicle, but I recommend checking them with a circuit tester # PTW2993 to be sure.

Then I recommend making sure your trailer has ground wires that are bare metal to metal and free of corrosion or debris. There is normally a common ground to the frame, but you will also want to check to see if there are ground connections at each tail light. Sometimes the lights utilize the mounting hardware as the ground.

expert reply by: Jason S