Left Hand Trailer Turn Signal Only Works with Right Hand Trailer Turn Signal

Question:

Hi there, I have an 04 Silverado 2500 HD with factory tow package and 7 pin wirng. Everything operates as is should except through my trailer wiring only the right signal activates both right and left on the trailer plug only. The truck lights work correctly Ive checked for frayed or damaged wires, and repaired a few cracked ones. Ive tested with the trailer, portable lights, and a trailer test plug. All the same results. Does that mean the problem exists in my turn signal relay? Would replacing the relay solve the problem? Or are the multiple potential causes for this? Any advice would be greatly appreciated. Thank you.

asked by: Jim

Expert Reply:

If I am understanding you correctly then you are saying that the left hand turn signal lights on the trailer only activate when the right hand turn signal lights are engaged? If this is the case then it does not sound like a turn signal relay but rather corrosion on the trailer connectors or a bad ground to either the trailer connectors or lights. The ground issue is attributed to nearly 75% of lighting troubles so this would be the first thing I check. The lighting assemblies will be either grounded to a wire or the mounting hardware. Regardless of which ground the light uses, I recommend removing it and sanding down the surface and then reattaching. You will want to do this with both trailer connectors as well but they will each have a separate ground wire. If the ground was not the issue then I recommend cleaning off the trailer connectors with some electrical contact cleaner.

Please report back to me on what you find or if you need additional advice.

expert reply by: Conner L