Troubleshooting Trailer Lights That Flash with Blinkers and Don't work When Brakes are Applied

Question:

I have an 04 avalanche with a factory hookup for 7 way trailer lights. Just recently I bought a trailer with 4 wire hookup. I bought an adapter at lowes that the 4 wire plugs into and then the adapter into my factory hookup. The trailer taillights work now but when I hit the brakes the right trailer light gos out, also the turn signals dont work, when I turn it just makes the trailer lights flash repeatedly. Anything I can do without a total rewire? thank you much Btw, its a 5x10 utility trailer and it doesnt have trailer brakes.

asked by: Nick H

Expert Reply:

First thing I would do is check for corrosion in the 7-way of your 2004 Chevy Avalanche and clean as necessary. Most of the time this fixes situations like this.

Aside from that the other most common problem is bad grounds on the trailer lights. You will want to make sure the grounds on the trailer light assemblies are connected to a clean metal surface. Also, the ground strap that runs from the trailer 4-way to the trailer frame needs to be connected to a clean metal surface.

Aside from those two things there could be cut or exposed wire somewhere on the trailer wiring that is circuits to short together and make random lights illuminate.

I attached a couple helpful FAQ articles for you to check out as well.

expert reply by: Jameson C