How to Determine Wiring Functions of Trailer When Trailer Uses Non-Standard Colors

Question:

Hi, I have an old trailer that I received already wired up. The trailer has 4 wires available for me to connect a flat 4-way connector: white, black, red, and brown. The 4-way flat connector I want to connect to the trailer wires have green, yellow, brown, and white wire. Ive tried connecting the wires in different combinations but cannot get any of the trailer lights to light up. I know the lights work, they were hooked up and working until someone kicked out the 4-way connector that was originally connected to the trailer wires while stepping over trailer hitch. I did not originally do the wiring so I am unsure as to how they had all the wires connected. Any suggestions or help with which wires should be connected? Any help is much appreciated, thanks. My next plan is just to start from scratch and rewire the trailer myself.

asked by: Nate

Expert Reply:

The trailer wiring colors you mentioned are the standard colors that trailer use. Green being right turn/stop, yellow being left turn/stop, brown being running lights, and white being ground.

So the easiest way to determine what your trailer wires control is to take a jumper wire from a 12 volt power source like a positive terminal on a vehicle battery and apply it to each of the wire colors. That will tell you which circuit they control. If you get a spark when you touch the wires that's the ground. Wire them according to what I listed in the first paragraph then.

expert reply by: Jameson C