How to Wire Trailer Clearance Lights with Black and Red Wires

Updated 08/05/2024 | Published 10/07/2019

Question:

Hi, marker lights have a two cables black and red,what we should connect to them brown cable and white cable?

asked by: Jan D

Expert Reply:

The brown wire for your trailer wiring should be for the running lights while the white wire should be for ground. Typically clearance lights use black for power and white for ground, like part # MCL32AB, but in the case of black and red wiring the black is typically ground while the red is for power.

This can vary between products but you can simply touch the black power from the light to the white wire from the trailer wiring and then the red wire to your brown wire. If that doesn't work then simply reverse the wiring and your light should work just fine.

expert reply by: Jon G

Great W.

10/29/2021

Helped answer my question thank You

Carl H.

8/5/2024

My travel trailer has 1 wire that is white and other is white and green on clearance light. Is white the ground? I am wiring up a camera and cannot experiment

Jon G.

8/5/2024

@CarlH Typically a solid white wire is used for a ground connection. You'll still want to test the wires though to verify this because each trailer is different and unless you've done all of the work on the trailer there's no telling who hooked what wire to which function.