indyplum

Not calling you wrong but are you trying the correct dummy plug ? I had the same problem and it turned out I was trying the wrong plug.The correct one that works for me is the one on the complete left side when facing the truck from the back. Hope this helps you also if needed the correct power lead is GM part # 23327843 on my receipt it is referred to as a F-HARNESS ( also called a tailgate wiring harness ????? ). I hope this may help you.