Door Sensor/Switch (For Alarm): Description and Operation
SYSTEM OPERATIONDoor Ajar Switch
The door ajar switches are integral to the door latches on each door. The switches close a path to ground for the Central Timer Module (CTM) when a door is opened, and open the ground path when a door is closed.
The door ajar switches cannot be repaired and, if faulty or damaged, the door latch unit must be replaced.