Troubleshooting Left Side Trailer Lights Not Working With 2022 GMC Sierra 3500

Updated 09/26/2024 | Published 09/10/2024

Products Featured in This Question

Hook Probe Circuit Tester

(72)

$13.47

7- and 4-Pole Trailer Connector Socket w/ Mounting Bracket - Vehicle End

(2718)

$44.78

Question:

I have recently purchased a 2022 GMC 3500 and no matter which trailer I hook up to the truck, my LH trailer lights do not work. Any suggestions?

asked by: Patrick W

Expert Reply:

Hello Patrick; since this has happened to multiple trailers it is definitely on the vehicle side. Start by checking the connector on the vehicle to make sure it isn't damaged and that no corrosion is present. If it appears to be fine, go ahead and double check the appropriate fuses/relays and make sure they're good. After that, it is time to start testing with a circuit tester # PTW2993.

I would assume you wouldn't have power at the connector itself but I would still start off here just to be sure. After checking the pin on the connector, move to the wire running into the connector from the back. If you have power behind the connector I would say the connector is the issue and replacing it with # HM40975 will solve your problem. If you do not have power here you will need to work your way back until you find a short. I would also double check your ground wire and make sure it is secure just to be thorough.

expert reply by: Robin H