Running Lights on Trailer Stay On All the Time

Updated 01/05/2015 | Published 01/03/2015

Question:

I have the trailer white wire hooked up as the ground wire. no lights work unless that wire is connected. all lights are now working however the tail lights and side running lights stay on all the time . I have tried the brown wire from the trailer to every wire and only one wire from plug will turn lights on but that is the wire that keeps them on constant

asked by: Leroy

Helpful Expert Reply:

This sounds like the problem could be a short or possibly ground related but based on what you have said a ground is much less likely. Look for any pinched or frayed wires on the trailer and fix as needed. This could cause a short resulting in constant power draw. Ground problems normally show up when there is more draw on a system such as when you have the running lights on and then use another function like a turn signal or brake light.

Make sure that the vehicle side and trailer side connectors are clean and free of corrosion inside and out. The main connector grounds should be attached to clean and corrosion free bare metal surfaces.

The light grounds should also be attached to clean and corrosion free bare metal surfaces. If there is anything between a light ground and the metal trailer frame or if the trailer has an aluminum frame, tilt bed, or folding tongue, any of these things can interrupt the ground. Running jumper wires from the light grounds to the main trailer connector ground can help.

expert reply by: Michael H