Troubleshooting Tail Lights Not Working on 4-Way Side But Working on 7-Way of Trailer Connector

Question:

I have a 7 blade / 4 flat molded adapter for my 2014 Silverado 1500. When I test for current I have BandT and Running lights on the seven blade. Testing the 4 flat plug on the same unit, I have only BandT. Thinking it was in the molded adapter, I purchased a new Hopkins plug, but have the same issue. This truck was factory wired for towing with adapter that snaps into the 7 blade / 4 flat plug, so am not thinking it is a wrong wire issue and certain it has nothing to do with the ground since the 7 works and the 4 does not. Interestingly when hooking the trailer up to my Ford Edge I have BandT as well as running lights on the trailer. What should I be looking for?

asked by: Noel D

Expert Reply:

I reached out to Hopkins to see if they have run into an issue like this and they said they have not. They recommend checking for continuity between the tail light circuit on the 4-way and 7-way with it disconnected from your truck and trailer. You will need a Multi Meter # PT29ZR to check for continuity. If there is no continuity then you know the connector is defective.

expert reply by: Bud M