How To Wire a Trailer Clearance and or Marker Light On a Trailer

Updated 03/13/2023 | Published 03/11/2023

Question:

My marker lights have black and yellow wires and appear to need a positive and negative run they light up when connected to a 9v battery. How do I wire these into the flat 4 wire harness on my camper? Black to brown, yellow to turn signal wire?

asked by: Robert L

Expert Reply:

I can't speak for all trailer clearance and or marker lights but most like the LED Trailer Clearance or Side Marker Light with Reflex Reflector part # 328-K-51 feature a simple two wire install, one for power and one for ground. If you aren't sure which wire has which function you can test them pretty easily with a battery or reach out to the light manufacturer. The above for example has a white wire for ground and a yellow wire for power. The ground wire will need to be attached to a bare metal surface and the power wire will need to be attached to the running light circuit on the trailer, usually brown. The lights are not tied into the stop/turn signal circuits.

I have attached a help article below which goes over the basic wiring for trailer lights.

expert reply by: Conner L