Question:
I have a 05 GMC Sierra 1500 everyone says I need to use the 3015-P but when I use that plug it doesn’t work if I plug in the 3025-P It seem to work I get power to the breaker control Which plug should I be using
asked by: Luis F
Expert Reply:
The # 3015-P and the # 3025-P are both very similar but for your 2005 GMC Sierra you SHOULD be using the 3015-P but since the difference is really just a wiring switch on the same connector it is possible yours may have already had that switch done. But at the end of the day if your controller is working fine with whichever harness I would just run that and not worry.
Tekonsha Plug-In Wiring Adapter for Electric Brake Controllers - GM