I also had the same problem on my
Chevy Based class C.
Open the drivers door and the dome light would not come on or when turning ignition off and exiting the radio would stay on,I also sometimes exit thru the coach and the radio would time out in 10 Min. This would not happen at times.
Most cars and trucks have a little plunger type switch in the door or the door frame that performs that function.
After some research I found that Chevy had put that function in the door latch itself. If the door latch doesn't fully close or open that switch will leave the power on. It is not a lot of movement.
I fixed it by cleaning the latch with contact cleaner and a light lube. You can use your finger to open and close the latch and see what I mean.
Another hint,if you want to see the mileage with out turning on the key just push that little button that switches the odometer from mileage to trip and the odometer will light up so you can see it.
Hopefully that will help,mine is 10 years older but knowing Chevy they sometimes don't change a lot of little things.
2006 TIOGA 26Q CHEVY 6.0 WORKHORSE VORTECFormer El Monte RV RentalRetired Teamster Local 692Buying A Rental Class C