Trailer LED Tail Light Stopped Working on Right Side

Question:

Hi there, The right side led turn/brake/park light stopped working on my cargo trailer. I pulled the light off the trailer. There are 3 wires: red, black and white. White appears to be connected to the metal frame black is connected somewhere although Imcannot tell where as its inside the wall frame of the trailer thered wire is not connected to anything it has a Marietta on it. Im thinking that the red should be connected somewhere. Is this my problem? Thanks for any help you can provide.

asked by: Trevor

Expert Reply:

It sounds like you are missing that 1 connection on the trailer tail light. Typically, a trailer tail light will have 2 or 3 wires. If it has 3 wires then there will be a ground wire (attached to the frame) a wire for brake lights and turn signal (these are the same wire) and a third wire for the running lights.

You can use a circuit tester such as # PTW2991 to test the black wire to see which functions it is carrying. Have someone run through the lighting functions in the tow vehicle to determine which functions it has. Whatever is missing must be what the red wire is for.

Usually when a light just stops working on one side it is a ground problem or a connection issue like a broken wire somewhere. Make sure the light is grounded to a clean and corrosion free bare metal surface and do the same with the main trailer connector ground.

The wiring inside the trailer frame makes it hard to determine if there is a break in the wiring. You could run a temporary wire from the light to the main trailer connector and if it starts working you know the wiring in the frame is bad.

Also make sure the tow vehicle and trailer connectors are clean and free of corrosion. I have included a link to a help article that shows how to test and troubleshoot for you to view.

expert reply by: Michael H