Troubleshooting Running Lights on Trailer Not Functioning

Question:

my running lights on my trailer with 7 pin do not work, siginals and breaks work

asked by: Eric

Expert Reply:

This could be a number of things but I would start by checking out the connectors on the trailer and vehicle side. Make sure they aren't damaged and are free of any debris or corrosion. It wouldn't hurt to clean them while you're at it. Assuming everything checks out here go ahead and test the connector on your 2021 Tacoma with a circuit tester like # PTW2993. If you have power here you know the problem is on the trailer side. If you don't it is on the vehicle side.

If it is on the trailer side you're looking at a short or bad ground. Make sure the ground is secure on a clean, bare-metal surface. You can test the wire running back to the lights while checking for a short. Repair as necessary. I highly doubt both running lights went out at the same time but it is not unheard of. If you have power to both but no lights they either have burned out bulbs or need to be replaced.

If it is on the vehicle side it will be a similar process. Check the ground connection then check for a short in the wiring and repair as necessary. If your Tacoma has the tow package you will also want to check the trailer running light fuse to make sure it isn't blown.

expert reply by: Robin H