Troubleshooting No Running Lights on Trailer Towed by 2014 Dodge Ram

Question:

I have brake lights and turn signals but no running light coming out of the truck and I checked the fuses they are good

asked by: William F

Expert Reply:

If your trailer's turn and brake lights work properly but the running/tail lights do not this usually indicates a ground problem on the trailer or vehicle wiring harnesses.

If there is a weak ground connection at either the vehicle or trailer the wiring may be able to deliver enough power to operate functions like turn and brake lights (which do not remain on continuously) but not be able to deliver the higher current required by tail lights, which remain on continuously.

First check the main ground wire on the trailer. This needs to make a solid metal-on-metal connection to the trailer frame. You can sand off the grounding point to remove rust, paint, primer, etc and then reattach the ground wire or you can move the ground ring terminal to a new spot on the frame. You want bare metal on bare metal for the best possible ground. Apply dielectric grease # 11755 at the connection to help prevent entry of water and other contaminants.

If this does not correct the problem then repeat the ground wire check on the vehicle side.

expert reply by: Adam R