Troubleshooting Malfuntioning Lights on Trailer Towed by 1999 Chevy Silverado

Question:

I have a 1999 Silverado. The tail lights worked perfectly until a few days ago. Now I have right turn light only. No brake, tail or left turn light. The trailer lights work perfect on my other truck. I would appreciate any information you can share. Thank you

asked by: Tommy H

Expert Reply:

I am assuming you are speaking of the trailer lights here. Since the trailer works fine when tested on a different vehicle, you have effectively eliminated the trailer as being the problem.

Take a look at the trailer connector on your Silverado. Make sure it is not damaged or corroded. If you can see any green corrosion on the pins or sockets on the connector, it might be preventing the signal from getting through to the trailer. If the connector looks fine, use a circuit tester on the wiring leading to the connector. If you do not have a circuit tester, we offer an inexpensive one, part # 3808. Activate the left turn signal, and probe the yellow wire to see if you are getting a signal. Do the same with the right turn while testing the green wire and the brown wire while checking the brown wire. Also ensure that the white wire is grounded to the vehicle and that the grounding connection is made to clean metal.

If all of these items check out, please let me know and we will try some other possibilities.

I have provided a link to our wiring FAQ page which offers a great deal of information about trailer wiring, as well as some wiring diagrams that your might find helpful.

expert reply by: Mike L