Side Marker Light Wiring Installation

Question:

My wiring kit came with side markers with both a yellow wire and a black wire. Which do i connect to the main brown wire? Is the other wire a ground?

asked by: Mike V

Helpful Expert Reply:

It sounds like you're trying to connect new side marker lights on your trailer. I can help you determine which wire is which, but since it's an unknown product there's just no way to know.

There are two ways to test which wires are which. The first would be to test the lights on a battery- place the black wire on the positive terminal and the yellow wire on the negative. If the lights power up as they would in normal working fashion, the black will be the power and the yellow will be the ground wire- connect the black to the brown wire and ground the yellow wire. If they don't power up normally, test the functions the opposite way and make sure the light powers up as they should and then you can connect the yellow to brown and black to ground.

The other way to test would just be a trial and error; connect the wires black to brown and yellow to ground. If they work, problem solved, otherwise you'll have to switch them around.

If these lights have a dual function, you can test which function works on which wire in the same fashion, but since in this case the hardware will ground the lights, you'll need to have the lights installed on your trailer to test which wire runs which function. A part that we offer that acts in this manner would be the Submersible Optronics Trailer Lights # TL5RK .

expert reply by: Erik B