Door/Trunk Ajar Indicator/Lamp: Description and Operation

Door Ajar Indicator Description and Operation

Door Ajar Indicator System Components

The door ajar indicator system consists of the following components:

* Body control module (BCM)

* Instrument panel cluster

* Driver door latch

* Passenger door latch

* Left rear door latch

* Right rear door latch

* Liftgate latch

* Rear compartment lid latch

* Driver window motor

Driver Door Ajar (AXG)

The driver window motor supplies a 12 V signal to the door ajar switch within the door latch, when the driver door is open the door ajar switch closes pulling the 12 V signal low. When the driver window motor detects the drop in the 12 V signal circuit, it will then communicate this status to the BCM via local interconnect network (LIN) bus. The BCM communicates with the instrument cluster via serial data message. The instrument panel cluster, upon receipt of this serial data message, will illuminate the driver door ajar indicator and also send a serial data message to the radio to activate the door ajar audible warning when the vehicle speed is greater then 8 km/h (5 mph).

Driver/Passenger/Rear Door Ajar (Without AXG)

The body control module (BCM) supplies a 12 V signal to each of the door latches, these latches contain an ajar switch which is normally open when the door is closed. When a door is ajar or open, the contacts of the ajar switch will close causing the voltage in the signal circuit to drop to zero volts. The BCM will detect the voltage drop and will send a message to the instrument panel cluster. The instrument panel cluster, upon receipt of this message, will illuminate the appropriate door ajar message in the driver information center and also send a message to the radio to activate the door ajar audible warning when the vehicle speed is greater then 8 km/h (5 mph).

Trunk/Liftgate Ajar

The body control module (BCM) provides a 12 V signal to the trunk ajar signal circuit. The liftgate latch and the rear compartment lid latch contain an ajar switch which is normally open when the trunk or liftgate is closed. When the liftgate or trunk or is opened, the normally open ajar switch closes. With the ajar switch closed, ground is provided to the ajar switch signal circuit. The BCM detects the voltage drop and sends a serial data message to the instrument panel to display the door ajar indicator