Wiring for Lights on a Boat Trailer.

Question:

I cant figure out what the white wire with a green stripe and another white wire with a yellow stripe are for on my trailer, it has a yellow, white, 2 green, one with yellow striper and one with brown stripe, they go together. any suggestions, or wiring diagrams available ? ps, its a boat trailer

asked by: BOB R

Expert Reply:

There can always be differences in wiring colors from one manufacturer to the other. Typically you will have a white ground, a green right turn and brake, a yellow left turn and brake and two browns one to go down each side of the trailer for running lights. I have attached a video I did showing this in more detail. I've also linked a typical diagram of this.

With your wiring colors being non traditional I recommend using a circuit tester like the LCD Digital Circuit Tester part # PTW2992. You can use this to test the wiring to figure out what does what by going through the light functions on your tow vehicle and test it after your trailer plug to see what wires carry what signals. If you dont have a connector on the wiring and you're trying to add a plug end you can ground a battery to your trailer then touch each of the wires to the positive terminal of the battery and see what trailer lights come on. The brake and turn signal wire will be a brighter light than the tail light is.

expert reply by: Randy B