How to Connect 4-Way Trailer Wiring with a Wishbone Harness

Updated 10/21/2016 | Published 10/20/2016

Products Featured in This Question

16 Gauge, 4 Conductor Bonded Parallel Wire - Per Foot

(237)

$2.47

20 Ft 4-Way Trailer Wiring Harness - Wishbone Style - 30" Ground

(333)

$17.94

Hook Probe Circuit Tester

(65)

$12.94

Question:

On trailer theirs white green with brown line brown with green line yellow with brown line brown Im tried hook up to solid white brown green yellow plug where do the wires go

asked by: Justyn S

Expert Reply:

You have a wishbone harness like # A20WB. This type of wiring harness splits the running light circuit at the trailer connector, so you don't have to run a jumper wire from taillight to taillight. The yellow/brown wire is the running light circuit for the driver side. The green/brown wire is the running light circuit for the passenger side.

It's good idea to test your vehicle wiring for each function using a circuit tester like part # PTW2993. You'll connect the wiring based on function and not necessarily color. Vehicle wiring colors do not always match up directly with trailer wiring.

Here a list of standard wiring and functions.
White - Ground
Brown -Tail/Running Lights
Green - Right Turn/Brake
Yellow - Left Turn/Brake

I have linked a FAQ wiring article for additional info.