Troubleshooting Trailer Lights Not Working After Rewiring Trailer

Question:

I ran new wires on a used trailer I bought brake lights didn’t work. I got only the turn signals to blink but nothing else then they stopped working. I ran a ground wire all the way to the light to get it to blink. But now nothing.

asked by: Ian H

Expert Reply:

I am happy to help.

First using a circuit tester like # PTW2993 test the trailer connector on your tow vehicle while a friend presses the brakes and turns on the turn signals.

If you are getting power on the connector, then you will need to double check the trailer wiring. Start with making sure the main ground on the tongue of the trailer is secure to bare corrosion free metal.

Next check the trailer connector for any debris or corrosion that could be causing power to not make it to the lights.

Using the circuit tester, test the wires leaving the connector for power while the trailer is connected to your tow vehicle, if you are not getting power then the issue is in the connector, and it will need to be replaced.

If you are getting power keep checking the wires to see where the power stops.

Since you mentioned that you rewired the trailer but did not mention replacing the taillights it is possible a bulb is burnt out, or the light has an internal issue. You can test this by removing the taillight and touching the ground to the negative terminal of a 12v battery and the other wires one at a time to the positive terminal.

If the lights don't light up, you will need to replace them.

If you are needing replacements just send me a picture of the lights and the dimensions and I would be happy to recommend a replacement.

I included a link to a helpful article on wiring for you to take a look at.