So I noticed in between the driver and rear seat of my 2017 Chevy Silverado 1500 LT underneath the truck was a harness hanging there. I looked up the part number to see what it's purpose was, because I couldn't find anywhere it plugged into. The part number is PBT-GF30. Can someone help me with this? Also my truck is idling in between 500rpm to a little over 1,000rpm when the truck is in park. I changed the intake air flow sensor but didn't do the trick.