Installing 7-way Trailer Connector to Non-Typical Trailer Wiring Colors

Question:

Want to connect trailer wires. Its a 7 pin plug. Wires are orange green pink purple black brown blue

asked by: Bronwin

Expert Reply:

The usual wire color codes are shown in the trailer wiring help article I've linked for you. Since the wire colors you mention aren't typical, you'll need to do a little detective work.

If the unknown wires are on the tow vehicle itself, you can determine each wire's function by using a circuit tester like # PTW2993. Have a helper activate each lighting function like the right turn, left turn and running lights and make note of which wires have voltage according to which function is currently being activated. Through a process of elimination, you can identify all the wires. Blue would almost certainly be the output from the brake controller to the trailer brakes, and black is most likely ground.

If the unknown wires are on the trailer, you'll need a 12 volt battery with it's negative post grounded to the trailer frame. Attach a length of wire to the positive post, and apply to each of the unknown wires, making note of what activates as each circuit is powered up.

Wire color codes aren't absolute, the vehicle manufacturers can change them at any time which is why we recommend folks wire by function, not by color.

expert reply by: Mike L