Operation

OPERATION

The door ajar switches are actuated by the mechanisms internal to the door latch. When a door is closed and properly latched, its door ajar switch is an open circuit. When a door is open or only partially latched, the door ajar switch is a closed circuit. The door ajar switches are hard wired in series between a body ground and the ElectroMechanical Instrument Cluster (EMIC) (also known as the Cab Compartment Node/CCN).

The EMIC reads the hard wired door ajar switch inputs through internal pull-ups, then uses these inputs to control many electronic functions and features of the vehicle. The EMIC also sends the proper electronic door ajar switch status messages to other electronic modules in the vehicle over the Controller Area Network (CAN) data bus.

The door ajar switches as well as the hard wired inputs and outputs of the switches may be diagnosed using conventional diagnostic tools and procedures. Refer to the appropriate wiring information.