Part 8A
OVERDRIVE OFF INDICATORAn overdrive off indicator is standard equipment on all instrument clusters. However, on vehicles not equipped with the optional overdrive automatic transmission, this indicator is electronically disabled. The overdrive off indicator consists of the text OO/D OFF", which appears in the lower portion of the electronic gear selector indicator Vacuum Fluorescent Display (VFD). The VFD is part of the cluster electronic circuit board, and is visible through a cutout located in the lower right corner of the cluster overlay. The dark lens of the VFD prevents the indicator from being clearly visible when it is not illuminated. The text "O/D OFF" appears in an amber color and at the same lighting level as the gear selector indicator information when it is illuminated by the instrument cluster electronic circuit board. The overdrive off indicator is serviced as a unit with the VFD in the instrument cluster.
The overdrive off indicator gives an indication to the vehicle operator when the OFF position of the overdrive off switch has been selected, disabling the electronically controlled overdrive feature of the automatic transmission. This indicator is controlled by the instrument cluster circuit board based upon cluster programming and electronic messages received by the cluster from the Powertrain Control Module (PCM) over the Programmable Communications Interface (PCI) data bus. The overdrive off indicator receives battery current on the instrument cluster electronic circuit board through the fused ignition switch output (run-start) circuit whenever the ignition switch is in the ON or Start positions; therefore, the indicator will always be OFF when the ignition switch is in any position except ON or Start. The indicator only illuminates when it is switched to ground by the instrument cluster circuitry. The instrument cluster will turn ON the overdrive off indicator for the following reasons:
- Bulb Test - Each time the ignition switch is turned to the ON position the overdrive off indicator is illuminated for about two seconds as a bulb test.
- Overdrive OFF Lamp-ON Message - Each time the cluster receives an overdrive off lamp-on message from the PCM indicating that the OFF position of the overdrive OFF switch has been selected, the overdrive OFF indicator will be illuminated. The indicator remains illuminated until the cluster receives an overdrive OFF lamp-OFF message from the PCM, 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 overdrive OFF indicator will be turned ON, then OFF again during the VFD portion of the test to confirm the functionality of the VFD, and again during the bulb check portion of the test to confirm the functionality of the cluster control circuitry.
The PCM continually monitors the overdrive OFF switch to determine the proper outputs to the automatic transmission. The PCM then sends the proper overdrive off lamp-ON and lamp-OFF messages to the instrument cluster. For further diagnosis of the overdrive off indicator or the instrument cluster circuitry that controls the indicator, (Refer to INSTRUMENT/CLUSTER - DIAGNOSIS AND TESTING). For proper diagnosis of the overdrive control system, the PCM, the PCI data bus, or the message inputs to the instrument cluster that control the overdrive off indicator, a DRB III scan tool is required. Refer to the appropriate diagnostic information.
SEAT BELT INDICATOR
A seatbelt indicator is standard equipment on all instrument clusters. The seatbelt indicator is located in the Information Center area of the instrument cluster, to the right of center. The seatbelt indicator consists of a stencilled cutout of the International Control and Display Symbol icon for "Seat Belt" 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 lens behind the cutout in the opaque layer of the overlay causes the icon to appear in red through the translucent outer layer of the overlay when the indicator is illuminated from behind by a Light Emitting Diode (LED) soldered onto the instrument cluster electronic circuit board. The seatbelt indicator is serviced as a unit with the instrument cluster.
The seatbelt indicator gives an indication to the vehicle operator of the status of the driver side front seatbelt. This indicator is controlled by a transistor on the instrument cluster circuit board based upon cluster programming and a hard wired input from the seatbelt switch in the driver side front seatbelt retractor through the seat belt indicator driver circuit. The seatbelt indicator Light Emitting Diode (LED) receives battery current on the instrument cluster electronic circuit board through the fused ignition switch output (run-start) circuit whenever the ignition switch is in the ON or Start positions; therefore, the indicator will always be OFF when the ignition switch is in any position except ON or Start. The LED only illuminates when it is switched to ground by the instrument cluster transistor. The instrument cluster will turn ON the seatbelt indicator for the following reasons:
- Seatbelt Reminder Function - Each time the cluster receives a battery current input on the fused ignition switch output (run-start) circuit, the indicator will be illuminated as a seatbelt reminder for about seven seconds, or until the ignition switch is turned to the OFF position, whichever occurs first. This reminder function will occur regardless of the status of the seatbelt switch input to the cluster.
- Driver Side Front Seatbelt Not Buckled - Following the seatbelt reminder function, each time the cluster detects an open circuit on the seat belt indicator driver circuit (seatbelt switch open - seat- belt unbuckled) with the ignition switch in the Start or ON positions, the indicator will be illuminated. The seatbelt indicator remains illuminated until the seat belt indicator driver input to the cluster is closed to ground (seatbelt switch closed - seatbelt buckled), 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 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 seatbelt switch input to the instrument cluster circuitry can be diagnosed using conventional diagnostic tools and methods. For further diagnosis of the seatbelt indicator or the instrument cluster circuitry that controls the LED, (Refer to INSTRUMENT CLUSTER - DIAGNOSIS AND TESTING).
SECURITY INDICATOR
A security indicator is standard equipment on all instrument clusters. However, on vehicles not equipped with the optional Vehicle Theft Security System (VTSS), this indicator is mechanically disabled. The security indicator is located in the Information Center area of the instrument cluster, to the left of center. The security indicator consists of a stenciled cutout of the word "SECURITY" 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 lens behind the cutout in the opaque layer of the overlay causes the "SECURITY" text to appear in red through the translucent outer layer of the overlay when it is illuminated from behind by a Light Emitting Diode (LED) soldered onto the instrument cluster electronic circuit board. The security indicator is serviced as a unit with the instrument cluster.
The security indicator gives an indication to the vehicle operator when the Vehicle Theft Security System (VTSS) is arming or is armed. On models equipped with the Sentry Key Immobilizer System (SKIS), the security indicator also gives an indication to the vehicle operator of the status of the SKIS. This indicator is controlled by a hard wired input to the instrument cluster from the Central Timer Module (CTM) on the VTSS indicator driver circuit and, if the vehicle is so equipped, by a transistor on the instrument cluster circuit board based upon electronic messages received by the cluster from the Sentry Key Immobilizer Module (SKIM) over the Programmable Communications Interface (PCI) data bus. The security indicator Light Emitting Diode (LED) receives battery current on the instrument cluster electronic circuit board at all times through the fused B(+) circuit at all times; therefore, the LED will remain functional regardless of the ignition switch position. The LED only illuminates when it is provided a path to ground by the CTM or by the instrument cluster transistor. The security indicator will be illuminated for the following reasons:
- Bulb Test - If the vehicle is equipped with SKIS, each time the ignition switch is turned to the ON position the security indicator is illuminated by the instrument cluster for about three seconds based upon an electronic lamp-ON message received from the SKIM as a bulb test. There is no bulb test performed for models that are not equipped with the optional SKIS.
- VTSS Indication - During the seventeen second VTSS arming function, the CTM will flash the security indicator ON and OFF repeatedly at a steady, fast rate to indicate that the VTSS is in the process of arming. Following successful VTSS arming, the CTM flashes the security indicator ON and OFF continuously at a slower rate to indicate that the VTSS is armed. The security indicator continues flashing at the slower rate until the VTSS is disarmed or triggered. If the VTSS alarm is triggered, the CTM will flash the security indicator at a steady, fast rate for up to eighteen minutes or until the triggering condition is removed, before returning to the slower, armed flash rate.
- SKIM Lamp-ON Message - Each time the cluster receives a lamp-ON message from the SKIM, the security indicator will be illuminated. The indicator can be flashed ON and OFF, or illuminated solid, as dictated by the SKIM message. The indicator remains illuminated solid or continues to flash until the cluster receives a lamp-off message from the SKIM, or until the ignition switch is turned to the OFF position, whichever occurs first. For more information on the SKIS and the security indicator control parameters, (Refer to VEHICLE THEFT SECURITY/SENTRY KEY IMMOBILIZER SYSTEM - OPERATION).
- Actuator Test - Each time the instrument cluster is put through the actuator test, the security 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 provides a hard wired ground input to the instrument cluster circuitry through the VTSS indicator driver circuit whenever the ignition switch is in the OFF position and the VTSS is arming, armed, or triggered. Whenever the ignition switch is in the ON or Start positions, the SKIM performs a self-test to decide whether the system is in good operating condition. The SKIM then sends the proper lamp-ON or lamp-OFF messages to the instrument cluster. For further diagnosis of the security indicator or the instrument cluster circuitry that controls the indicator, (Refer to INSTRUMENT CLUSTER - DIAGNOSIS AND TESTING). If the SKIS turns ON the security indicator after the bulb test, either solid or flashing, it indicates that a SKIS malfunction has occurred or that the SKIS is inoperative. The VTSS indicator driver circuit input to the instrument cluster can be diagnosed using conventional diagnostic tools and methods. For proper diagnosis of the VTSS, the CTM, the SKIS, the PCI data bus, or the message inputs to the instrument cluster that control the security indicator, a DRB III scan tool is required. Refer to the appropriate diagnostic information.
SERVICE 4WD INDICATOR
A service 4WD indicator is standard equipment on all instrument clusters. However, on vehicles not equipped with the optional four-wheel drive system and electronically shifted transfer case, this indicator is electronically disabled. The service 4WD indicator is located in the Information Center area of the instrument cluster, to the right of center. The service 4WD indicator consists of a stencilled cutout of the words "SERVICE 4WD" 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. An amber lens behind the cutout in the opaque layer of the overlay causes the "SERVICE 4WD" text to appear in amber through the translucent outer layer of the overlay when the indicator is illuminated from behind by a Light Emitting Diode (LED) soldered onto the instrument cluster electronic circuit board. The service 4WD indicator is serviced as a unit with the instrument cluster.
The service 4WD indicator gives an indication to the vehicle operator when the Transfer Case Control Module (TCCM) has recorded a Diagnostic Trouble Code (DTC) for an electronic transfer case circuit or component malfunction. 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 TCCM over the Programmable Communications Interface (PCI) data bus. The service 4WD indicator Light Emitting Diode (LED) receives battery current on the instrument cluster electronic circuit board through the fused ignition switch output (run-start) circuit whenever the ignition switch is in the On or Start positions; 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 service 4WD indicator for the following reasons:
- Bulb Test - Each time the ignition switch is turned to the ON position the service 4WD indicator is illuminated for about two seconds as a bulb test.
- Service 4WD Lamp-ON Message - Each time the cluster receives a lamp-ON message from the TCCM, the indicator will be illuminated. The indicator remains illuminated until the cluster receives a service 4WD lamp-off message from the TCCM, or until the ignition switch is turned to the OFF position, whichever occurs first.
- Communication Error - If the cluster receives no messages from the TCCM for six seconds, the service 4WD indicator is illuminated by the instrument cluster to indicate a loss of TCCM communication. The indicator remains controlled and illuminated by the cluster until a valid message is received from the TCCM.
- Actuator Test - Each time the cluster is put through the actuator test, the service 4WD 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 TCCM continually monitors the electronic transfer case switch and circuits to determine the condition of the system, then sends the proper messages to the instrument cluster. For further diagnosis of the service 4WD indicator or the instrument cluster circuitry that controls the LED, (Refer to INSTRUMENT CLUSTER - DIAGNOSIS AND TESTING). For proper diagnosis of the TCCM, the PCI data bus, or the message inputs to the instrument cluster that control the service 4WD indicator, a DRB III scan tool is required. Refer to the appropriate diagnostic information.