Troubleshooting Trailer Wiring that Intermittently Works as Well as Intermittent Connection

Published 10/28/2022

Question:

I have a 2020 Silverado with the in-vehicle trailering app/diagnostics. Boat trailer has all LED lights, including backup lights, each light individually grounded to frame with a ground wire, and frame directly grounded across the swing-away tongue to the white wire at the plug. All grounds, wiring, lights are good condition. Intermittently all trailer lights together either work or dont work and in-vehicle display says no trailer connected. Sometimes it will say no trailer detected but the lights on the trailer are in fact on. There is no pattern to when the lights work or not. Chevrolet dealer tested the trailer lighting control module and said it worked fine. What do you suggest? Thanks!

asked by: Brent

Helpful Expert Reply:

Normally this is corrosion or dirt on the pins of the trailer connectors that only requires some sanding to get rid of and fix. If you already checked for that it could also be a bent pin on the connectors as well. The "no connection" light on the display is related to the connection on the brake output circuit of the brake controller. That circuit is what decides if a trailer is connector or not so that would be one place to start with. Swing away couplers often cause issues too if the ground connector runs to the frame before the actuator. If all of the lights are stopping at the same time that would mean it's a ground wire issue since that's only circuit they all have in common that can take all the lights out.

I attached a help article on trailer wiring troubleshooting for you to check out as well.

expert reply by: Jameson C