Troubleshooting Trailer Wiring When Lights Are Not Working

Updated 08/07/2014 | Published 08/06/2014

Products Featured in This Question

Hook Probe Circuit Tester

(70)

$13.94

Dielectric Grease for Electrical Connectors, 2 oz.

(1508)

$9.54

Question:

Hi, my trailer wire is not working, what can I do to test whats wrong with it.

asked by: Aaron

Expert Reply:

To test the wiring on your trailer, you will need a circuit tester like part # PTW2993. The first thing you want to do is test the wiring connector at the back of your vehicle. If the connector checks out, then you can move to the trailer for testing.

If none of the trailer lights are working, you can test the wires on the back of the trailer-side connector with the circuit tester when it is attached to the vehicle. If the wires from the connector test okay, you can move to the lights that are attached to the lights that are not working. start checking the wires to see if any are pinched, cut, or damaged in any way. Make sure the ground wires are all attached to a clean bare metal surface and are free from corrosion or rust.

When working with electrical connections I recommend using dielectric grease like part # 11755. This keeps dirt and moisture out of the electrical connections and helps prevent corrosion.

I have attached some helpful articles that explain trailer wiring and also how to troubleshoot wiring.

expert reply by: Jeffrey L