Running Lights on Trailer Impeding the Brake Lights from Working

Question:

My running lights on my trailer impede the stop lights from working. In day time every thing works without the running lights. Grounding works in each scenario. suggestions?

asked by: Rob M

Expert Reply:

This could still be a grounding issue. Though the grounding wire may test successfully, there could still be corrosion or buildup that is preventing a full enough connection to power everything at the same time.

I would start by cleaning the connection points or moving them to another point if that is easier. Once finished, test the main ground on the vehicle and trailer again.

I've included a link to our 4 and 5-Wire Troubleshooting page.

If that does not solve the problem, I would look at the connector to see if there is any corrosion on the pins. Clean those if necessary as well.

If none of the above work, then you may have to inspect the wires themselves and check for any damage or pinch points.

expert reply by: Kef G