What is Second Wire on Clearance Light for

Question:

My side marker light have two wires yellow and black coming out the back. I know the yellow wire connect to the trailer harness brown wire but where does the black wire connect?

asked by: Nancy

Expert Reply:

Since clearance lights only carry the running/tail light function, if your clearance light has 2 wires that means 1 would be for power and 1 would be for ground. If you check out the Optronics Light # AL82AB you can see that the black wire is for power and the white is for ground.

You can either tie your ground wire into the main ground circuit or you can simply add a ring terminal # DW05702-1 and ground it to the frame on your trailer with a self-tapping screw # FA1131822. The ring terminal installation is a better connection for your ground but it has to be touching a clean, bare-metal surface on your frame.

Attached is a video of this light being installed on a trailer for you to reference.

expert reply by: Jon G