How To Install Trailer Light With Green, Black, Red, And Two White Wires On Trailer With Two Wires

Question:

Hi have a 1973 trailer. Im replacing the rear lights but only have a brown and white wire. The ground is through the chasis. I have two lights on the new light fixture - one with red and white and one with green, black and white - can you let me know how to wire for stop, signal and lights?

asked by: Graeme

Expert Reply:

I would be happy to help!

Even though your old lights grounded through the mounting hardware, the new lights you have ground through the white wire. You will need to either add a ring terminal like # DW05702-1 and secure each one to the frame, or run a wire from the main ground on the tongue to each white wire using # 16-1-1.

Now for the other wires you will need to confirm the function. You will need to connect the red, green, and black wires to the positive terminal of a 12v battery while grounding the white wires on the lights and see which functions light up. More than likely the light that has both the green and black wires will be the turn signal and stop lights, and the light with the single red wire will be the running lights.

Since your trailer has a brown and white wire which are not the standard colors for a trailer, you will need to hook the trailer up to your tow vehicle and have a friend apply the brakes, turn signals, and running lights one at a time while you use a circuit tester like # PTW2993 to see which function each wire has.

From there you will just need to make the connections based on function.

I included a link to a helpful article on wiring for you to take a look at.