Door Switch: Description and Operation

AJAR SWITCH

DESCRIPTION

DOOR
This vehicle has four door ajar switches, one for each door. Each switch is concealed within and integral to its respective door latch unit. The switches are momentary leaf contact-type units that are actuated by the mechanisms internal to the door latch. A short pigtail wire and connector on each door latch connects the door ajar switch to the vehicle electrical system through its respective door wire harness. The door ajar switches cannot be adjusted or repaired and, if ineffective or damaged, the door latch unit must be replaced.

FLIP-UP GLASS
A flip-up glass ajar switch is standard equipment in this vehicle. This switch is concealed within and integral to the flip-up glass latch. The switch is a momentary leaf contact-type unit that is actuated by the flip-up glass latch mechanism. An integral dedicated connector receptacle on the flip-up glass latch connects the flip-up glass ajar switch to the vehicle electrical system through the tailgate wire harness. The flip-up glass ajar switch cannot be adjusted or repaired and, if ineffective or damaged, the latch unit must be replaced.

TAILGATE
A tailgate ajar switch is standard equipment in this vehicle. This switch is concealed within and integral to the tailgate latch unit. The switch is a momentary leaf contact-type unit that is actuated by the mechanism internal to the tailgate latch. A pigtail wire harness and connector on the tailgate latch connects the tailgate ajar switch to the vehicle electrical system through the tailgate wire harness. The tailgate ajar switch cannot be adjusted or repaired and, if ineffective or damaged, the latch unit must be replaced.

OPERATION

DOOR
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 between a body ground and the Body Control Module (BCM). The front door ajar switches are connected to the BCM through a driver or passenger door ajar switch sense circuit, while the rear door ajar switches are connected to the BCM through a left or right rear door ajar switch sense circuit. The BCM reads the door ajar switch status through an internal pull-up, then sends electronic door ajar switch status messages to the ElectroMechanical Instrument Cluster (EMIC) over the Programmable Communications Interface (PCI) data bus and uses these inputs to control many electronic functions and features of the vehicle.

The door ajar switches can be diagnosed and tested using conventional diagnostic tools and procedures. Refer to the appropriate wiring information. However, conventional diagnostic methods may not prove conclusive in the diagnosis of the BCM, the EMIC, the PCI data bus, or the electronic messaging used to convey door ajar switch status to other modules in the vehicle. The most reliable, efficient, and accurate means to diagnose the BCM, the EMIC, the PCI data bus, and both the hard wired and electronic message inputs and outputs affected by the door ajar switch inputs requires the use of a diagnostic scan tool.

FLIP-UP GLASS
The flip-up glass ajar switch is actuated by the flip-up glass latch mechanism. When the flip-up glass is closed and properly latched, the flip-up glass ajar switch is an open circuit. When the flip-up glass is open or only partially latched, the flip-up glass ajar switch is a closed circuit. The flip-up glass ajar switch is hard wired between a body ground and both the Body Control Module (BCM) and the rear wiper motor.

The output of the switch is connected to the BCM and rear wiper motor through a flip-up glass ajar switch sense circuit. The BCM reads the flip-up glass ajar switch status through an internal pull-up, then sends electronic flip-up glass ajar switch status messages to the ElectroMechanical Instrument Cluster (EMIC) over the Programmable Communications Interface (PCI) data bus and uses this input to control many electronic functions and features of the vehicle. The rear wiper motor uses this input to restrict rear wiper operation when the flip-up glass is ajar.

The flip-up glass ajar switch can be diagnosed and tested using conventional diagnostic tools and procedures. Refer to the appropriate wiring information. However, conventional diagnostic methods may not prove conclusive in the diagnosis of the BCM, the EMIC, the PCI data bus, or the electronic messaging used to convey flip-up glass ajar switch status to other modules in the vehicle. The most reliable, efficient, and accurate means to diagnose the BCM, the EMIC, the PCI data bus, and both the hard wired and electronic message inputs and outputs affected by the flip-up glass ajar switch inputs requires the use of a diagnostic scan tool.

TAILGATE
The tailgate switch is actuated by the mechanism internal to the tailgate latch. When the tailgate is closed and properly latched, the tailgate ajar switch is an open circuit. When the tailgate is open or only partially latched, the tailgate ajar switch is a closed circuit.

The tailgate ajar switch is hard wired between a body ground and the Body Control Module (BCM). The output of the switch is connected to the BCM through a tailgate ajar switch sense circuit. The BCM reads the tailgate ajar switch status through an internal pull-up, then sends electronic tailgate ajar switch status messages to the Electro- Mechanical Instrument Cluster (EMIC) over the Programmable Communications Interface (PCI) data bus and uses this input to control many electronic functions and features of the vehicle.

The tailgate ajar switch can be diagnosed and tested using conventional diagnostic tools and procedures. Refer to the appropriate wiring information. However, conventional diagnostic methods may not prove conclusive in the diagnosis of the BCM, the EMIC, the PCI data bus, or the electronic messaging used to convey tailgate ajar switch status to other modules in the vehicle. The most reliable, efficient, and accurate means to diagnose the BCM, the EMIC, the PCI data bus, and both the hard wired and electronic message inputs and outputs affected by the tailgate ajar switch input requires the use of a diagnostic scan tool.