Both Turn Signals Light Up and All Lights Go Out with Brake Lights On Boat Trailer

Question:

I am trying to figure out what is going on with the wiring on my boat trailer. All the original wires were carotid very badly, so I decided to just replace all of them. I am having issues with both turn signals coming on when only one is turned on, and every time the brakes are applied all trailer lights go off. Also when I connect the passenger side lights on the trailer they become very dim. Is this a ground problem? Any advice will help...

asked by: Caleb

Expert Reply:

It does sound like a ground issue. Ground problems normally show up when there is more draw on a system such as when you have the running lights on and then use another function like a turn signal or brake light.

Make sure that the vehicle side and trailer side connectors are clean and free of corrosion inside and out. The main connector grounds should be attached to clean and corrosion free bare metal surfaces.

The light grounds should also be attached to clean and corrosion free bare metal surfaces. If there is anything between a light ground and the metal trailer frame or if the trailer has an aluminum frame, tilt bed, or folding tongue, any of these things can interrupt the ground. Running jumper wires from the light grounds to the main trailer connector ground can help.

expert reply by: Michael H