How To Wire In Aftermarket Trailer Tail Lights With Red, Black, And White Wires

Updated 12/15/2020 | Published 12/12/2020

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Question:

My 4 way wiring has a white one brown one yellow one and a green one. The after market tail light has red black and white which one goes where

asked by: Paul

Expert Reply:

The wire functions for your 4-way connector are White is the ground, green is right turn signal, yellow is left turn signal, and brown is the running lights.

On the aftermarket tail light the most likely wire functions are the white wire is the ground, the red wire is the turn signals/Brake light wire, and the black wire is the tail light wire.

You would install the white wire to white wire, brown wire to black wire on each tail light, green wire to red wire on the right side light, and the yellow wire to the red wire on the left tail light. I highly recommend using heat shrink butt connectors # DW05744-10 to make a weather tight connection.

If you can tell me which aftermarket tail light you purchased I would be happy to confirm that these are the correct functions, or you can test the red and black wires by using a jumper wire with one end connected to a 12v battery and the other end connected to either the red or black wire to see which function illuminates.

I included a helpful article on trailer wiring for you to take a look at.

expert reply by: Samuel C