When Running Lights are On Turn Signal Circuits Do Not Work on 2005 Chevy Colorado Wiring Harness

Updated 08/09/2013 | Published 08/08/2013

Question:

I am having electrical trouble with the wiring to the 4-plug connector. I have a 2005 Chevy Colorado with a T connector previously installed for a 4-plug trailer connection. I have eliminated the trailer as being the problem because I am using a 4-plug trailer circuit tester at the 4-plug connection. The running lights work without any problem and the turn signals work properly when the running lights are off. When the running lights are on, the turn signals do not operate. I installed a new ground wire from the white wire to the frame between the 4-plug and the tail light converter box. Still the problem persists. Could this be a tail light converter gone bad or something else?

asked by: Jonathan

Expert Reply:

Normally when there is more load on a circuit, like when the running lights are on and drawing constant power, that is when ground issues show up. I know you have moved the ground once already but try moving it to another location and/or sanding down the bare metal surface for the best connection. To test this you can run a length of wire from the converter ground wire to the negative battery terminal. If the problem goes away then you know an alternate ground location will work to fix the issue.

If the problem persists then it could be an issue inside the converter at which point the harness will need to be replaced. I have included some links that will help with troubleshooting the wiring further.

expert reply by: Michael H