Tips for Wiring Up 7-Way on Trailer Where Wire Colors Dont Match Standard

Updated 03/20/2017 | Published 03/18/2017

Question:

I have a trailer with a 7 way on it. I cant seem to figure out how the wires go. I dont have a multimeter to test the wires. The colors presented are Green black white yellow Yellow/brown and green brown tied together and a red. The trailer has brakes that I can tell. Its a car hauler.

asked by: Chris

Expert Reply:

Wire colors aren't always consistent which can be very frustrating. Your options are to run a jumper wire from a 12 volt source like a car battery to each of the circuits to see which lights come on or trace each of them back to where the terminate. Most likely the white is ground though so you wouldn't need to run power there. If you do you should see a spark.

I attached a picture that shows how a 7-way is normally wired up as well as a help article that has info on how trailers are typically wired as well.

Normally only a circuit tester like part # PTW2993 is used when trying to figure out how to wire up a 7-way on a tow vehicle. It's not as helpful when on the trailer side.

expert reply by: Jameson C