How to Connect a Clearance Light with a Single Wire to a Trailer with Two Wires

Updated 10/21/2020 | Published 10/19/2020

Products Featured in This Question

Optronics Thinline LED Trailer Fender Light w/ Bracket - Submersible - 10 Diodes - Amber/Red Lens

(807)

$10.75

Ring Terminal -16-14 Gauge - 1/4" Ring ID - Qty. 1

(67)

$1.21

Deka Heat Shrink Butt Connector - 16-14 Gauge - Nylon Insulation - Blue - Qty 5

(1095)

$7.31

Question:

1wire clearance light with 2 wires coming from train is there a positive and negative to identify

asked by: David T

Expert Reply:

You can definitely wire a clearance light with a single wire to a trailer that has two wires.

The first thing to know is that the two wires from the trailer are not positive and negative. Rather, they are the running light wire and the grounding wire. The running light wire (usually brown or black, but sometimes another color) is the wire that you connect to the wire coming from the light. To do this, use a butt connector like part # DW05744-5.

The ground wire (usually white) from your trailer is supposed to connect the ground wire of a clearance light in the same way as the power. However, lights with single wires have a self-grounding ring. I've linked to a video review of the Optronics Thinline LED Fender Light, part # MCL67ARB, to illustrate this. To get the trailer's ground wire to connect to that ring, put a ring terminal like part # DW05702-1 on the end of the wire and attach that to the mounting bolt/screw on the ground side of your clearance light.

expert reply by: Kef G