Troubleshooting Ground on Trailer Wiring on 2004 Chevy Silverado 2500 HD

Updated 04/15/2019 | Published 04/12/2019

Products Featured in This Question

Pollak Replacement 7-Pole, RV-Style Trailer Connector Socket - Vehicle End

(745)

$15.54

Dielectric Grease for Electrical Connectors, 2 oz.

(1491)

$11.28

Question:

if I check truck plug ,everything checks ok. Plug in a trailer and the only thing that works are the side marker light on led taillights. No turn signals, no tail lights, no brake lights or 4 ways. If I plug trailer in another trucks every thing works. so problem is in truck, but, I dont know what to look for . I checked all fuses. Help!

asked by: TERRY K

Expert Reply:

Most likely the issue you're having with your trailer lights not functioning is due to a weak ground. The tester you use on the truck's socket does not draw much power at all, nowhere near the current drawn by the actual trailer lights when the trailer is connected. This is why the truck tests okay but still does not activate the trailer lights.

I suggest you locate and disconnect the trailer socket's ground wire on the Silverado. Sand off the grounding point to expose clean bare metal, clean the ring terminal too, as needed, and apply dielectric grease like # 11755 before you securely re-attach the ground wire. The grease is not conductive but it blocks water and dirt from getting in the way of your new ground connection.

expert reply by: Adam R