2008 Tahoe LTZ 5.3L Gas, 50,102 miles on the clock

Problem: Interior lights DO NOT come on when I open DRIVER DOOR, but they do light when remaining doors and liftgate open.

Question 1: Could this be a defective door switch? If so, would you know the part number for it and can it be replaced easily?

Question 2: I noticed there are red lenses on all 4 door panels. Are they supposed to light up when the doors open as well as the front floor?

Hope someone out there can help!

 

Yep, sounds like a bad door switch to me. Local parts store should have it

 

I noticed a small empty square on the pillar just above the lock, could this be where the switch is supposed to be? Where is it located? The only other thing I see is the door harness going into the side of the truck at the front of the door.

 

I think the door switches must be internal now as I've never seen an exposed one like the older vehicles used to have. Somebody else here may know where they are.