Contour Enthusiasts Group Archives Forums General Common Interests Trailer Lighting

I'm having problems wiring some lights on a trailer. The lights have 3 wires coming from them. I assumed that they were running, turn/brake, and ground. The wires are Red, White, and Black. I assumed that Red was running, White was turn/brake, and Black was ground. I wired them up like I thought but when the headlights are turned on, the lights are super bright. When the brakes or turn signal is depressed, they dim down, but do flash with the turn signals. I tried reversing the Red and White, with the same result. Anyone have any ideas why this might be happening?

Thanks for any help!

I would take a 12 volt battery and some jumper wires. I would run the battery Ground directly to the trailer's frame. Then connect the positive to each of the three trailer wires and see which light lights up. If the black wire is ground then it will create a short circuit and there will be a big arc when you try to connect the wire.

The brake and turn signals use the same circuit.

Usually the colors are;

White = Ground
Brown = Tail lights
Yellow = Left turn
Green = Right turn

If you are trying to wire a car/truck that has separate turn and brake lights to a trailer where they are one piece you will need a Converter. These use diodes to change the currents to the tail lights. They are sold at most parts stores.