How to Determine Function of Trailer Wiring Colors by Function When Non-Standard Colors are Used

Question:

Im installing new led trailer tail lights on my light trailer. The wires from the trailer are black, green, yellow, yellow/brown, and yellow/green. From the led lights are brown, green, yellow, and white. Please tell me which wires go to which wires. I am having a difficult time. Thank you

asked by: Jeff B

Expert Reply:

You'll have to use a circuit tester like part # 3808 to test all of the wires on your trailer when you apply the various turn/brake signals so that you can identify what each wire carries. And then you can use a jumper wire from a 12 volt battery to each of the wires on the new light to determine the function of each. Most likely white is ground though just from looking at the picture.

Aside from that there's no way to for sure know what the color wires all carry function wise.

expert reply by: Jameson C