How to Install 3-Wire LED Type Light to 4-Pole Wiring

Updated 05/10/2017 | Published 05/08/2017

Question:

I need to know how and what wires do I uses to hook up a 4 flat plug to run a 3 wire led lights or will this not work thank you

asked by: Michele

Expert Reply:

A flat 4-pole trailer harness carries three lighting circuits, brake lights, running lights and turn signals. The green wire carries right side turn and brake signals; the yellow wire carries left side turn and brake lights; and the brown wire on the 4-pole carries running lights for both sides of the trailer. You can refer to the linked article for more on trailer wiring.

How you connect your LED light depends on which light functions it supports and what you want it to do. If for example your light was a red light that works for all three light functions above, such as part # STL59RB which also has 3 wires, you would connect its white wire to ground, the black wire to the running light circuit (brown wire on the 4-pole) and the red wire to the brake/turn circuit wires.

expert reply by: Adam R