What Circuit Does Trailer License Plate Light Tap Into

Question:

I purchased a trailer tag holder with a light. Has black and white wire. Also purchased roll of trailer wire and adapter with stop and turn signal lights. 4 wire flat with multi colors. What color wire do I connect the black and white tag wires to?

asked by: Max J

Expert Reply:

The license plate light of a trailer will need to tap into the running light circuit of your trailer wiring. The white wire of the light will be the ground and would need to get ran to the frame of the trailer and the black wire will be the power wire for the light and would get ran to the running light circuit.

Typically the brown wire of trailer wiring is the running light circuit. This will be the pin closest to the jacketed pin on the 4-way (the ground).

I attached a help article on trailer wiring for you to check out as well.

expert reply by: Jameson C