Trailer Right Brake Light Goes Out with Left Turn Signal and Brakes On

Question:

So I got the Curt trailer lighting kit for the car and a trailer light kit. So the issue Im having is that all light functions work exept when the left signal is on with and without the lights on and the brakes are on, the right light turns off or dims when lights are on. There is continuity from the ground to all connections through the trailer plug. The car ground has continuity from the plug end to the body of the car and all connections have voltage on car. Anything I should try? Im am super frustrated

asked by: Richard

Expert Reply:

This is a text book example of a weak ground. Ground issues normally show up when there is more draw on a system. With a turn signal on and the brakes you are drawing a lot of power and that is when the issue is going to show up. You will want to start by making sure all grounds from the vehicle to each of the lights are attached to clean and corrosion free bare metal surfaces.

If you have something grounded at the same location as other items, moving the ground(s) to another location may help. If the trailer has an aluminum frame, tilt bed, or folding tongue it will help to run jumper grounds from the lights to the main trailer connector ground. Also make sure that the trailer connectors are clean and free of corrosion.

I have included a couple of links that should help.

expert reply by: Michael H