Door ajar switch does not seem to work
 

I have a 2005 monte carlo ss. I noticed when I opened my drivers side door the dome light doesn't go on. When I open the passenger side it does. Similar behavior when I turn off the car, after market radio won't turn off automatically if driver door is opened, but turns off with the passenger door opening. This leads me to believe the door ajar switch isn't working on the driver door. I haven't found any good info on how this switch works, it seems it is part of the locking mechanism? The power locks all work fine. I dont have a door ajar message on the display. A minor inconvenience, but would be nice to fix. Is there any troubleshooting I can do or what part would need to be replaced? Is it just a mad connection on the door latch?