Troubleshooting Running Lights Not Working on Trailer with Running Lights Turned to Auto on Vehicle

Question:

Our 2017 Riverside Travel Trailer’s running lights will only work when our headlights are turned off of auto. Is this normal? Also our brake LED lights only partially work unless the trailer hitch ball is attached to the trailer. Is this normal?

asked by: Twana

Expert Reply:

The problems you are describing sound like a classic ground issue on the trailer. A weak ground connection somewhere isn't allowing for enough power to travel to the trailer lights when you also have the running lights on in the vehicle and it's also relying on a ground connection with the trailer ball, which shouldn't be the case.

What I recommend doing is checking the main harness ground on the trailer to make sure it's securely connected to a clean, bare metal surface that's free of any debris or corrosion. Even it looks okay it might be worth it to still remove it, stand down the surface, and reattach the wire. Also check the ground connection for the light assemblies themselves, whether they use a dedicated wire for this or ground through their mounting hardware.

Lastly inspect the connector on the trailer side for any dirt or corrosion that might be built up around the pins, cleaning out as needed.

If this doesn't resolve the issue please let me know and we can continue to troubleshoot. I have attached a great article that you might also find helpful.

expert reply by: Chris R