What Circuit for Trailer Wiring Usually Gets Ran to a License Plate Light

Question:

On the TL21RK wiring that goes into the wiring harness for hookup to vehicle, which wire what color do I splice into to activate a license plate light? The one I bought has a ground wire that hooks directly to the trailer frame, and one wire to power the light. I need to know which wire to splice into on the TL21RK to make the license plate light illuminate when I turn on the headlights.

asked by: Kurt S

Expert Reply:

The running light circuit of trailer wiring is what usually gets ran to a license plate light. The brown wire of the # TL21RK carries the running light circuit so this would be the correct circuit to use.

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

expert reply by: Jameson C