With Trailer Connected and Plugged in New LED Lights on Truck Do Not Work

Question:

I put led on my truck and they work fine but when I hook up to my trailer I have no running light on the back of my truck , everything works on trailer

asked by: Matt

Expert Reply:

I would need to know the year, make, and model of the truck and if it has a factory trailer wiring connector or an aftermarket one. And if it is aftermarket, is it connected in anyway to the tail light wiring on the truck, either through connectors or hardwired.

What could be happening is that the trailer lights are overdrawing power causing the truck lights to not work. Converting the trailer to LED lights would reduce the current draw if that is indeed the problem.

It could also be a short or a bad ground somewhere. 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