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 Driver Door Module (DDM) (also known as the door module or the door control module) or the Body Control Module (BCM) (also known as the Signal Acquisition and Actuation Module/SAM). The DDM or the BCM 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 DDM or BCM also sends electronic door ajar switch status messages 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. However, conventional diagnostic methods will not prove conclusive in the diagnosis of the door ajar switch or the electronic controls or communication between modules and other devices that provide some features of the interior lighting system. The most reliable, efficient, and accurate means to diagnose the door ajar switches or the electronic controls and communication related to interior lighting operation requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.