Wiring 4-Pole Trailer Wiring To Tail Lights With Only 3 Wires

Question:

Trailer wiring has white ,brown,green and yellow and lights have white,yellow and brown on left and on right side has white,yellow and brown

asked by: Randy

Expert Reply:

Hey Randy,

When it comes to trailer wiring there unfortunately isn't a standard color coding that manufacturers have to follow so you'll have to do a bit of investigating to determine the function of the wires on the trailer lights, unless you still have the wire diagram for the lights. White wires will more often than not be your ground, Brown wires are typically running lights, yellow and green are usually your stop/turn light function. If you have a 12v battery laying around you can bring it to the lights, ground the white wire to the frame, and then put power to the yellow and brown to see how they function.

Personally, I'd run the # 16-4B-1 with the brown to the running lights, yellow to your left turn/stop, green to your right turn/stop, and white for your ground. I've attached a link to one of our help articles below that has videos and pictures to help walk you through this process.

expert reply by: Kevin C