Troubleshooting Side Maker Lights Not Working When Going From 2-Wire Lights To 1-Wire Connections

Updated 09/19/2021 | Published 09/18/2021

Question:

I wanted to replace the marker lights on my reefer trailer. The old ones are 2 wire but the new ones are single wire. I took the first old one off and wired up the first new one but I now have no power to it and the rest of the old ones on that side quit working. The old ones on the opposite side are still burning. What happened?

asked by: Adrian

Expert Reply:

It sounds like when you connected your single wire marker light like the Optronics LED Trailer Clearance and Side Marker Light # MCL44AB1, your ground connection on that side was removed. This would cause all the other lights on that circuit to no longer work.

The single wire style marker lights ground themselves when through the mounting hardware. If your mounting hardware is not grounded to the frame and the frame back to the trailer connector you will not have a complete circuit.

If you remove the lens cap on your light you should see a wire with an eyelet for the mounting hardware to pass thorough. If your reefer trailer does not have a grounded structure you can remove that eyelet and run the ground wire from your trailer into the light and make the connection there if you have enough room. If the wire is long enough you may be able to run it outside of the housing to make the necessary connection.

expert reply by: Bud M