I have an 06 monte carlo LT 3.9, its recently reached 200k, and then all these things started happening at once.
1) The dome light would not shut off after the door was closed and car was locked.
2) Message on the dash says the door is open
3) Using the auto door lock button, after a few minutes the alarm cycles on and off every 10 minutes unless you open the car with the key and the dash reads theft attempted.

The battery drained completely down, I bought a new battery and it operated as normal. (with the exceptions of the problems noted earlier) Anybody ever experienced this, could it be the BCM?

P.S. i did remove the fuse for the dome light because i could not get it to shut off