bing tracking image
Q & A Icon

How Do Utility Trailer Lights Wire Up to the Trailer Wiring Harness.  


My new lights on trailer has black an red , I need to know witch colors go to red and what to black ? My harness has brown , green , yellow , white


Expert Reply:

The red wire is the turn signal wire and will be run to the green wire of your harness if its the right turn signal side, and the black wire will run to the brown wire of your harness. The yellow wire from your harness will run to the left turn signal red wire. The brown wire will also run to the black wire of this light also.

I attached an FAQ on trailer wiring for you to check out also.

expert reply by:
Jameson C

Amanda C.


I have a tail light with a red wire, and a trailer with a green, brown, yellow, and white wire. Where would I attach the red wire to? I thought I would attach it to the brown wire since my brown wire is my light function wire but when I attached it on my tail light did not work. I need help asap!

Etrailer Expert

Chris R.


Are there any other wires coming from the tail light? It's hard to go just by color alone because not all light assemblies use the same schematic. The brown wire on your trailer would be for running lights.

John B.


I need 2 know how 2 wire a 4 flat on a 2002 chevy tahoe for my trailer Thank u for yas time



2 wires both green from trailer. 1 green and 1 black wire on new tail light. How to hook up?

Etrailer Expert

Jacob H.


The best way to handle this would be to test your wires on your trailer and see which green wire is doing what. I recommend marking them with a piece of electrical tap to know the difference for future reference. You can then hook your light wires up to a 12V battery and see what functions work with the wires.



Hi I hope you can help me on the one as I'm trying to connect new lights on my boat trailer and dont know what wire to connect to what wire The trailer has a yellow brown white and red wire while the LED light has a red white green brown and brown and white wire what connects to what
Etrailer Expert

Jon G.


@Graham Trailer wiring colors can vary from application to application. Your best bet is to figure out which wire carries what function on your trailer wiring and then connect the corresponding wires from your LED lights correctly. You can accomplish this by hooking your trailer up to your tow vehicle and then using a circuit tester to test the wires while you run through the various light functions.

Product Page this Question was Asked From

Q & A Icon

Continue Researching

See More Q&A Expert Answers >>