06sierradenali

Currently have an 06 Sierra Denali with heated seat issues. Here are the scenarios that I have run into Driver side stays on unless I press passenger then it shuts off and vice versa if I put driver side on low power and the passenger side on high they both stay on a vice versa Both sides will stay on high setting on back, but if you switch either side to bottom/back then they both shut off Anyone have any idea what the issue could be

Looking for the 3 plastic plugs that are in the passenger and drivers door for an 06 Sierra crew. There are 2 right next to each other and one below the round rubber plug. Anyone have a part number for these