Wiring Trailer Using Wishbone Wiring Harness

Updated 04/18/2020 | Published 04/17/2020

Question:

I just replaced my wiring I ran it inside a plastic tube inside the channel of my trailer I have four colors of wiring I have green and brown and yellow and brown I have the green and brown on the left hand side of the trailer and the yellow and brown on the right hand side of the trailer I connected into the lights and nothing happened but I realize I have to have a white ground to the trailer right my question is I have four colors green and brown yellow and brown how do I connect I only 4 connector I have a white a I would think the white connects to the trailer as a ground the yellow connects to the yellow the green connect to the green but then I have 2 browns do I connect both of those browns to the 1 Brown

asked by: Mike C

Expert Reply:

You're almost there!

What you're describing is known as a wishbone harness. The running lamp circuit is split with one leg running down the driver side, the other running down the passenger. You'd join these two wires to the brown running light wire from the trailer connector. The brown/yellow is ran down the driver side and the brown/green is run down the drivers side, so it sounds like you have that backwards. The white ground wire from the trailer connector will need to be grounded to the trailer frame. Put a ring terminal on the end of the white wire and find the spot on the trailer tongue where you want to mount it. Sand a dime-sized area down to bare metal and attach that ring terminal to the trailer tongue using a self-tapping screw. Put a star washer between the ring terminal and the trailer tongue so it'll bite into the metal for a good connection. Once you drive the screw down, give the connection a shot of spray paint like Rustoleum to protect if from corrosion.

I've linked to our trailer wiring article, I hope you find it helpful.

expert reply by: Mike L