Troubleshooting Trailer Turn Signals that Both Blink When One is Applied

Question:

Attaching trailer to tow vehicle via 7 prong. All lights illuminate and blink when either left or right turn is signalled. i direct wired at trailer 4 prong and got same result, all lights on trailer lit regardless which prong was energized. I cleaned trailer ground. No change.

asked by: James

Expert Reply:

Sounds like the left and right stop/turn circuits are shorting out to each other somewhere. Typically this is a corrosion issue or cut or exposed wire. You will want to start at the connector looking for corrosion or bent pins and work your way to the wiring looking for cut or exposed wire making your way back to the light assemblies.

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

expert reply by: Jameson C