Door/Trunk Ajar Indicator/Lamp: Description and Operation

DOOR AJAR INDICATOR
A door ajar indicator is standard equipment on all instrument clusters. However, on vehicles not equipped with this optional feature, this indicator is electronically disabled. The door ajar indicator is located in the Information Center area of the instrument cluster, to the left of center. The door ajar indicator consists of a stencil-like cutout of the words "DOOR AJAR" in the opaque layer of the instrument cluster overlay The dark outer layer of the overlay prevents the indicator from being clearly visible when it is not illuminated. A red Light Emitting Diode (LED) behind the cutout in the opaque layer of the overlay causes the "DOOR AJAR" text to appear in red through the translucent outer layer of the overlay when the indicator is illuminated from behind by the LED, which is soldered onto the instrument cluster electronic circuit board. The door ajar indicator is serviced as a unit with the instrument cluster.

The door ajar indicator gives an indication to the vehicle operator that one or more of the passenger compartment doors may be open or not completely latched. This indicator is controlled by a transistor on the instrument cluster circuit board based upon cluster programming and electronic messages received by the cluster from the Central Timer Module (CTM) over the Programmable Communications Interface (PCI) data bus. The door ajar indicator Light Emitting Diode (LED) is completely controlled by the instrument cluster logic circuit, and that logic will allow this indicator to operate whenever the instrument cluster receives a battery current input on the fused ignition switch output (run-start) circuit. Therefore, the LED will always be off when the ignition switch is in any position except On or Start. The LED only illuminates when it is provided a path to ground by the instrument cluster transistor. The instrument cluster will turn on the door ajar indicator for the following reasons:

- Bulb Test - Each time the ignition switch is turned to the On position the door ajar indicator is illuminated for about two seconds as a bulb test.

- Door Ajar Lamp-On Message - Each time the cluster receives a door ajar lamp-on message from the CTM indicating that a door is open or not completely latched, the door ajar indicator will be illuminated. The indicator remains illuminated until the cluster receives a door ajar lamp-off message from the CTM, or until the ignition switch is turned to the Off position, whichever occurs first.

- Actuator Test - Each time the cluster is put through the actuator test, the door ajar indicator will be turned on, then off again during the bulb check portion of the test to confirm the functionality of the LED and the cluster control circuitry

The CTM continually monitors the door ajar switches to determine the status of the doors. The CTM then sends the proper door ajar lamp-ON and lamp-OFF messages to the instrument cluster. For further diagnosis of the door ajar indicator or the instrument cluster circuitry that controls the indicator, (Refer to ELECTRICAL/INSTRUMENT CLUSTER - DIAGNOSIS AND TESTING). For proper diagnosis of the door ajar switches and circuits, (Refer to ELECTRICAL/LAMPS/LIGHTING - INTERIOR/DOOR AJAR SWITCH - DIAGNOSIS AND TESTING). For proper diagnosis of the CTM, the PCI data bus, or the electronic message inputs to the instrument cluster that control the door ajar indicator, a DRB III scan tool is required. Refer to the appropriate diagnostic information.

LIFTGATE AJAR INDICATOR
A liftgate ajar indicator is standard equipment on all instrument clusters. However, on vehicles not equipped with this optional feature, this indicator is electronically disabled. The liftgate ajar indicator is located in the Information Center area of the instrument cluster, to the left of center. The liftgate ajar indicator consists of a stencil-like cutout of the words "GATE OPEN" in the opaque layer of the instrument cluster overlay The dark outer layer of the overlay prevents the indicator from being clearly visible when it is not illuminated. A red Light Emitting Diode (LED) behind the cutout in the opaque layer of the overlay causes the "GATE OPEN" text to appear in red through the translucent outer layer of the overlay when it is illuminated from behind by the LED, which is soldered onto the instrument cluster electronic circuit board. The liftgate ajar indicator is serviced as a unit with the instrument cluster.

The liftgate ajar indicator gives an indication to the vehicle operator that the passenger compartment liftgate may be open or not completely latched. This indicator is controlled by a transistor on the instrument cluster circuit board based upon cluster programming and electronic messages received by the cluster from the Central Timer Module (CTM) over the Programmable Communications Interface (PCI) data bus. The liftgate ajar indicator Light Emitting Diode (LED) is completely controlled by the instrument cluster logic circuit, and that logic will allow this indicator to operate whenever the instrument cluster receives a battery current input on the fused ignition switch output (run-start) circuit. Therefore, the LED will always be off when the ignition switch is in any position except On or Start. The LED only illuminates when it is provided a path to ground by the instrument cluster transistor. The instrument cluster will turn on the liftgate ajar indicator for the following reasons:

- Bulb Test - Each time the ignition switch is turned to the On position the liftgate ajar indicator is illuminated for about two seconds as a bulb test.

- Liftgate Ajar Lamp-On Message - Each time the cluster receives a liftgate ajar lamp-on message from the CTM indicating that the liftgate is open or not completely latched, the liftgate ajar indicator will be illuminated. The indicator remains illuminated until the cluster receives an liftgate ajar lamp-off message from the CTM, or until the ignition switch is turned to the Off position, whichever occurs first.

- Actuator Test - Each time the cluster is put through the actuator test, the liftgate ajar indicator will be turned on, then off again during the bulb check portion of the test to confirm the functionality of the LED and the cluster control circuitry.

The CTM continually monitors the liftgate ajar switch to determine the status of the liftgate. The CTM then sends the proper liftgate ajar lamp-on and lamp-off messages to the instrument cluster. For further diagnosis of the liftgate ajar indicator or the instrument cluster circuitry that controls the indicator, (Refer to ELECTRICAL/INSTRUMENT CLUSTER - DIAGNOSIS AND TESTING). For proper diagnosis of the liftgate ajar switch and circuits, (Refer to ELECTRICAL/LAMPS/LIGHTING - INTERIOR/LIFTGATE AJAR SWITCH - DIAGNOSIS AND TESTING). For proper diagnosis of the CTM, the PCI data bus, or the electronic message inputs to the instrument cluster that control the liftgate ajar indicator, a DRBIII(R) scan tool is required. Refer to the appropriate diagnostic information.