When headlights are on, Left Turn Signal Does Not Work After Wiring a 2006 Toyota Corolla

Question:

Hello, Im noticing that the 55542 didnt have a grounding wire. Im assuming that because its using the grounds in the cars own system that its hooked into. Wondering if youd have any ideas ,other than improper grounding why , when my headlights are on, none of the lights on the left side of the trailer work but the right works fine. When my headlights are off, all the trailer lights behave properly.

asked by: LeRoy H

Expert Reply:

It sounds like you have a bad ground connection. You are correct that the # 55542 harness uses the vehicle ground, so I would turn my attention to the trailer. If all ground connections are not making good contact to bare metal, when the tail lights are turned on then the trailer lights will go out or not function properly.

You will need to check all of the ground connections especially where the taillights are mounted to the trailer frame, and where the light brackets are mounted if they are bolted to the frame. If a plastic license plate holder is mounted between the left side taillight and the trailer frame this could be the problem.

Once you have all of ground connections checked, if the problem persists, I would take the # 55542 wiring harness connectors apart and make sure none of the pins in the connectors are bent. If not reinstall the harness making sure all the connectors click into place properly. Then test the functions going into the converter on the harness and coming out with a circuit tester, item # PTW2993 if needed. If the functions going in are correct and not coming out, then the converter has most likely been shorted and will need to be replaced. We have a video showing how to test the wiring harness for proper function, see link.

expert reply by: Robert G