Troubleshooting Trailer Ground to Restore Operation of Running Lights

Question:

I have a 2014 Ram 2500 I just totally rewired a trailer that I restored Ive got all lights working turn signals brake lights, clearance lights but when I turn on my hazard light on they work but not when I turn on my headlights

asked by: Jeff F

Expert Reply:

What you describe sounds like the classic case of a weak primary ground on the trailer. Most of the time when a trailer's running lights do not work the cause is a main ground connection that can't quite pass enough current for all light functions to operate. Since running lights stay on continuously (unlike brake and turn lights) they will cause more current to be drawn through the wiring and so this light function tends to reveal a grounding issue.

The simplest remedy usually is to remove the main ground wire's ring terminal from the frame and sand off that spot to reveal clean bare metal. Apply protective dielectric grease # 11755 to that clean surface and tightly re-secure the ground ring terminal to the frame. If this does not correct the issue you can repeat this same process on the Ram's wiring harness ground wire.

expert reply by: Adam R