Troubleshooting Trailer Lights Not Working Using Hopkins LED Night-Glow Adapter

Updated 05/26/2019 | Published 05/23/2019

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Question:

The adapter lights up when I turn my headlights on but my trailer lights do not operate. My question, since the adapter lights up, does that mean there is power to the adapter and the trailer light issue is in the trailer?

asked by: Tim M

Expert Reply:

That is very likely the case. With that being said the Hopkins adapter # 37335 doesn't use all of the lighting functions to light up so you need to test it to be sure. Use a circuit tester, like part # PTW2993, to test each pin coming out of the adapter. Run through the lighting functions on the truck as you test it to see if the pins all work there. If they do the problem is on the trailer. If they don't work, then unplug the adapter and do the same test on the pins of your truck's 7-way. If everything works here, then the adapter must be bad. If you're still not getting all of the functions here, then I'd start by cleaning the connector and retesting. Then, check any trailer fuses as well as the connector's ground location. It needs to be grounded to a clean bare metal surface. If the connector and fuses are good, then you need to inspect the wiring of the truck for any damaged wires.

If you found the issue to be on the trailer start by cleaning its connector and ground location. If you still haven't found the issue, then you need to trace the trailer wiring looking for any damage or pinched points.

If you still can't locate the problem, let me know and we'll keep troubleshooting.

expert reply by: Charles S