Door Contact Switches, Purpose/Design/Function

Purpose
The status of the vehicle doors (open, closed) is indicated as an electrical signal by the door contact switches.

Design
The door contacts are designed as normally closed switches. (Switching contacts are open when doors are closed).

Function
If the door is open, the door contact switch then connects an input of the pneumatic system equipment (PSE), combined functions (A37) to ground. The PSE transmits the status as a CAN message.