Troubleshooting Utility Trailer Running and Side Marker Lights Not Working

Updated 05/06/2019 | Published 05/03/2019

Products Featured in This Question

Standard Trailer Light Kit with 25' Wire Harness

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$28.55

Hook Probe Circuit Tester

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$13.33

Question:

Lowe’s 5x8 utility trailer Running lights and side markers don’t work

asked by: Brian J

Expert Reply:

If the running lights and side markers aren't working at all on your utility trailer, then the first thing you will want to do is test the running lights pin on your tow vehicle's connector. Use a circuit tester like # PTW2993 to test the pin while the running lights are activated in the vehicle.

If you get power, there then you know the problem is on the trailer but if you don't then there's an issue on the vehicle side. If you didn't get power the most likely culprit is a blown or missing fuse/relay under the hood. Check your copy of the vehicle's owner's manual for the appropriate fuse locations and make sure they are present and in good condition. Also inspect the connector itself for any debris or corrosion that needs to be cleaned out.

If you did get power, then there's a problem with the trailer wiring. First inspect the trailer connector for any debris or corrosion that needs to be cleaned. Then you will just want to try and trace the wiring going to the light assemblies and look for any pinched, exposed, or damaged sections that needs to be replaced. You can also make sure the light assemblies are securely grounded to a clean bare metal surface, whether they ground with a dedicated wire or through their mounting hardware.

If you still aren't able to locate and resolve the issue, please let me know and we can continue to troubleshoot. I have also attached a wiring troubleshooting article that you might find helpful.

expert reply by: Chris R