Where is the door ajar sensor on a 2001 Chevrolet Malibu?

The door ajar sensor on a 2001 Chevrolet Malibu is located within the door itself, in the door latch mechanism. There's one sensor per door. You won't see it easily without removing the door panel. It's a small switch that's activated when the door is closed, completing a circuit and signaling to the car that the door is shut.