Troubleshooting Trailer Backup Light Not Working After Installing Curt 5th Wheel/Gooseneck Wiring

Updated 10/22/2025 | Published 09/25/2025

Question:

put in the wiring harness and working fine in my 2025 Chevy Silverado 2500 however, the backup light on the trailer does not work with this harness. I still works in the factory bumper plug with the harness installed just not in the curt plug.. is this a problem with the harness or is not included for the new campers.

asked by: Richard B

Expert Reply:

Hi Richard; have you tried testing the pin on the Curt 5th Wheel/Gooseneck # C53CR 7-way for power? I would start there. Since the light works on your trailer with the 7-way at the bumper I expect it to work with the gooseneck wiring as well. If you don't have power on the reverse light pin I would double check the connections.

Go ahead and unplug the wiring and plug it back in to make sure everything is properly seated, this is likely the issue. This includes the connector in the truck bed as well as the connections in-line with your bumper wiring. If that doesn't fix it, test the wire at the connector for power. If you have power here but not at the connector in the truck bed it may be that it still isn't fully seated or you got a bad connector.

expert reply by: Robin H

Curt 5th Wheel/Gooseneck Custom Wiring Harness
(click to enlarge)

Robin H.

10/22/2025

Hey Richard, did re-seating the connectors on your Curt 5th wheel/gooseneck harness get the trailer’s backup light working again? Knowing what fixed it could help others sorting out the same wiring issue.