GMC 2008 Acadia SLT-1 "battery hinge" Questions

need to replace thermostat batteries, can't open Hi, I have an old (early 80s) thermostat in a not very accessible spot. Can't remember how to open it to replace the batteries, and don't want to force

...the key from the ignition. Do you know why? The sound stayed on for two days and it killed my battery The place to start for this is at the door switch itself. You will notice a small button or ...