Troubleshoot Right Stop/Turn Circuit on Trailer that Doesnt Work When Headlights are On

Updated 08/07/2017 | Published 08/05/2017

Question:

When the trailer lights are on, the right turn signal doesnt work. Lights off on trailer, they all work.

asked by: Elaine H

Helpful Expert Reply:

You've got a weak ground on the right trailer turn assembly, or you have a short between the running light circuit and the right stop/turn circuit. Here's how you tell which you have. If when the head lights are on the running right taillight assembly is brighter than the other side (meaning the brighter stoplight circuit is active) then the issue is a short between the two circuits.

If instead the circuit is the same brightness (or dimmer) then the issue is a weak ground. You can improve the ground by cleaning up how the assembly grounds to the trailer or by running a ground wire from the assembly back to the main ground harness of the trailer.

expert reply by: Jameson C