Door/Trunk Ajar Indicator/Lamp: Description and Operation
AJAR INDICATORSDESCRIPTION
Door, hood, liftgate, liftglass ajar indicators are standard equipment on all instrument clusters. The hood ajar function is active only in vehicles equipped with a hood ajar switch, which is available only in certain markets where it is required equipment. The ajar indications appear within the reconfigurable dot matrix Organic Light Emitting Diode (OLED) display unit. The ajar indicators are capable of displaying numerous combinations of textual messages and icons which appear in place of the compass/trip computer information in the dot matrix display.
The dot matrix OLED is soldered onto the cluster electronic circuit board, and is visible through a window with a smoked clear lens located on the lower edge of the tachometer gauge dial face of the cluster overlay. The dark lens over the OLED prevents it from being clearly visible when it is not illuminated. The ajar indicator textual messages and icons appear in the same blue-green color and at the same lighting level as the compass/trip computer information when they are illuminated by the instrument cluster electronic circuit board.
The ajar indicators are serviced as a unit with the OLED in the instrument cluster.
OPERATION
The ajar indicators give an indication to the vehicle operator that one or more of the passenger compartment doors, the hood, the liftgate or the liftgate flip-up glass may be open or not completely latched. These indicators are controlled by the instrument cluster logic circuit based upon cluster programming and hard wired inputs received by the cluster from the door, liftgate and liftgate flip-up glass ajar switches as well as from hood ajar switch status messages received over the Controller Area Network (CAN) data bus from the Front Control Module (FCM).
The ajar indicator function of the reconfigurable dot matrix Organic Light Emitting Diode (OLED) display unit is completely controlled by the instrument cluster logic circuit, and that logic will only allow this indicator to operate when the instrument cluster receives a battery current input on the fused B(+) circuit. Therefore, the OLED ajar indications can occur regardless of the ignition switch position. The instrument cluster will turn on an ajar indicator for the following reasons:
- Ajar Switch Input or Status Message - Each time the cluster receives a door, liftgate or liftgate flip-up glass ajar switch input indicating that a door, the liftgate or the liftgate flip-up glass or any combination of these is open or not completely latched with the ignition switch in any position, the appropriate ajar textual message and icons will be illuminated. A hood ajar indication happens only with the ignition switch in the ON or START positions. If the cluster detects a vehicle speed input greater than zero (kilometers or miles-per-hour) while the ignition switch is in the ON or START positions, the ajar indication will be accompanied by a single chime tone. When the ignition switch is in any position except ON or START, any and all ajar indications will time out after about five minutes.
The instrument cluster continually monitors the door, liftgate and liftgate flip-up ajar switches to determine the status of the doors, liftgate and liftgate flip-up glass. The FCM continually monitors the status of the hood ajar switch, then sends the proper hood ajar switch status messages to the instrument cluster. For proper diagnosis of the door, hood, liftgate and liftgate flip-up glass ajar switches and circuits, the cluster, the FCM, the CAN data bus, or the electronic message inputs to the instrument cluster that control the ajar indications, a diagnostic scan tool is required.