Installing 4-Way Connector on Trailer with 5 Wires

Question:

4-way plug, I have a white wire a green wire a yellow a brown and a yellow with black where does the yellow with black go thanks

asked by: Kevin W

Expert Reply:

If you have 5 wires on your trailer and a 4-pin connector, you most likely had what is called a wishbone harness on the trailer like # A35W42B. On a wishbone harness, you will have two wires attached to the running light circuit because there is one wire for each side of the trailer.

I recommend testing the wires on your trailer with a 12V battery so you can verify each of their functions. Going by color alone is not the best method, as manufacturers and aftermarket wiring can change up the traditional colors that are used. If you did in fact have a wishbone harness, most likely the yellow wire with a black stripe is for the left side running lights, but you will still want to test to be sure

I have attached an article on trailer wiring that you might also find helpful.

expert reply by: Chris R