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IndicatorsIndicators are located in various positions within the EMIC and are all connected to the EMIC electronic circuit board. The antilock brake system indicator, four-wheel drive indicators, headlamp high beam indicator, front/rear fog lamp indicator, and turn signal indicators are hard wired. The brake indicator is controlled by the hard wired park brake/ brake warning indicator switch input to the EMIC and the EMIC programming. The seatbelt indicator is controlled by the hard wired seat belt switch input to the EMIC and the EMIC programming. The Malfunction Indicator Lamp (MIL) is normally controlled by PCI data bus messages from the Powertrain Control Module (PCM); however, if the EMIC loses PCI data bus communications, the EMIC circuitry will automatically turn the MIL on and display the message "no BuS" in the odometer VFD until PCI data bus communication is restored. The EMIC uses PCI data bus messages from the PCM, Airbag Control Module (ACM), and the Sentry Key Immobilizer Module (SKIM) to control all of the remaining indicators. Different indicators are controlled by different strategies; some receive fused ignition switch output from the EMIC circuitry and have a switched ground, while others are grounded through the EMIC circuitry and have a switched battery feed.
In addition, certain indicators in this instrument cluster are configurable. This feature allows these indicators to be automatically enabled or disabled by the EMIC circuitry for compatibility with certain optional equipment. The airbag indicator, cruise indicator, and the Sentry Key Immobilizer System (SKIS) indicator are automatically configured. Once a configurable indicator is enabled by the EMIC, it is learned and stored in cluster memory for the remainder of the cluster life.
The hard wired indicators are diagnosed using conventional diagnostic methods. The EMIC and PCI bus message controlled indicators are diagnosed using the EMIC self-diagnostic actuator test. Proper testing of the PCI data bus and the data bus message inputs to the EMIC that control each indicator requires the use of a DRBIII scan tool. Refer to the appropriate diagnostic information. Specific operation details for each indicator may be found elsewhere in this service information.
ABS INDICATOR
An Antilock Brake System (ABS) indicator is standard equipment on all instrument clusters, but is only functional on vehicles equipped with the ABS option. The ABS indicator is located near the lower edge of the instrument cluster overlay, to the left of the odometer/trip odometer Vacuum-Fluorescent Display (VFD). The ABS indicator consists of a stencil- like cutout of the International Control and Display Symbol icon for "Failure of Anti-lock Braking System" 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 icon to appear in amber 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 ABS indicator is serviced as a unit with the instrument cluster.
The ABS indicator gives an indication to the vehicle operator when the ABS system is faulty or inoperative. This indicator is hard wired on the instrument cluster electronic circuit board, and is completely controlled by the Controller Antilock Brake (CAB). The ABS 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 CAB through the CAB relay in the Power Distribution Center (PDC). The CAB continually monitors the ABS circuits and sensors to decide whether the system is in good operating condition. The indicator is turned ON by the CAB for about 2 seconds after the ignition switch is turned to the ON position as a bulb test. After the bulb test, the CAB turns the indicator ON or OFF based upon the results of the ABS self-tests. If the CAB turns the indicator ON after the bulb test, it indicates that the CAB has detected a system malfunction and/or that the ABS system has become inoperative. The ABS indicator can be diagnosed using conventional diagnostic tools and methods.
AIRBAG INDICATOR
An airbag indicator is standard equipment on all instrument clusters However, on vehicles not equipped with airbags, this indicator is electronically disabled. The airbag indicator is located near the lower edge of the instrument cluster overlay to the right of the odometer/trip odometer Vacuum-Fluorescent Display (VFD). The airbag indicator consists of a stencil-like cutout of the International Control and Display Symbol icon for "Airbag" in the opaque layer of the instrument cluster overlay. The dark outer layer of the overlay prevents the indicator from being clearly visible when the 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 it is illuminated from behind by a Light Emitting Diode (LED) soldered onto the instrument cluster electronic circuit board. The airbag indicator is serviced as a unit with the instrument cluster.
The airbag indicator gives an indication to the vehicle operator when the airbag system is faulty or inoperative. The airbag 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 Airbag Control Module (ACM) over the Programmable Communications Interface (PCI) data bus. The airbag 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 provided a path to ground by the instrument cluster transistor.
The instrument cluster will turn ON the airbag indicator for the following reasons:
* Bulb Test - Each time the ignition switch is turned to the ON position the airbag indicator is illuminated for about 7 seconds. The first 2 seconds is the cluster bulb test function, and the remainder is the ACM bulb test function.
* ACM Lamp-ON Message - Each time the cluster receives a lamp-ON message from the ACM, the airbag indicator will be illuminated. The indicator remains illuminated for about 12 seconds or until the cluster receives a lamp-OFF message from the ACM, whichever is longer.
* Communication Error - If the cluster receives no airbag messages for 5 consecutive seconds, the airbag indicator is illuminated. The indicator remains illuminated for about 12 seconds or until the cluster receives a single lamp-OFF message from the ACM, whichever is longer.
* Actuator Test - Each time the cluster is put through the actuator test, the airbag 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 ACM continually monitors the airbag system circuits and sensors to decide whether the system is in good operating condition. The ACM then sends the proper lamp-ON or lamp-OFF messages to the instrument cluster. If the ACM sends a lamp-ON message after the bulb test, it indicates that the ACM has detected a system malfunction and/or that the airbags may not deploy when required, or may deploy when not required. The ACM will store a Diagnostic Trouble Code (DTC) for any malfunction it detects. Each time the airbag indicator fails to illuminate due to an open or short in the cluster airbag indicator circuit, the cluster sends a message notifying the ACM of the condition and stores a DTC. For proper diagnosis of the airbag system, the ACM, the PCI data bus, or the message inputs to the instrument cluster that control the airbag indicator, a DRBIII scan tool is required. Refer to the appropriate diagnostic information.
BRAKE/PARK BRAKE INDICATOR
A brake indicator is standard equipment on all instrument clusters. The brake indicator is located near the lower edge of the instrument cluster overlay, to the left of the odometer/trip odometer Vacuum-Fluorescent Display (VFD). The brake indicator consists of a stencil-like cutout of the word "BRAKE" 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 "BRAKE" text 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 brake indicator is serviced as a unit with the instrument cluster.
The brake indicator gives an indication to the vehicle operator when the parking brake is applied, or when there are certain brake hydraulic system malfunctions. This indicator is controlled by a transistor on the instrument cluster electronic circuit board based upon cluster programming, electronic messages received by the cluster from the Powertrain Control Module (PCM) over the Programmable Communications Interface (PCI) data bus, and hard wired inputs to the instrument cluster from the park brake switch and the brake warning indicator switch. The brake 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 brake indicator for the following reasons:
* Bulb Test - Each time the ignition switch is turned to the ON or Start positions the brake indicator is illuminated for about 4 seconds as a bulb test.
* Park Brake Switch Input - Each time the cluster detects ground on the red brake warning indicator driver circuit (park brake switch closed = park brake applied or not fully released) the brake indicator is illuminated solid. If a vehicle speed message is received by the cluster from the PCM over the PCI data bus indicating the vehicle is moving while the red brake warning indicator driver input is ground, the brake indicator is flashed ON and OFF repeatedly Whether illuminated solid or flashing, the indicator remains illuminated until the red brake warning indicator driver input to the cluster is an open circuit (park brake switch open = park brake fully released), or until the ignition switch is turned to the OFF position, whichever occurs first.
* Brake Hydraulic System Malfunction - Each time the cluster detects ground on the red brake warning indicator driver circuit (brake warning indicator switch closed = pressures in the two halves of the split brake hydraulic system are unequal) the brake indicator is illuminated solid. The indicator remains illuminated until the red brake warning indicator driver input to the cluster is an open circuit (brake warning indicator switch open = brake hydraulic system pressures are equal), or until the ignition switch is turned to the OFF position, whichever occurs first.
* Actuator Test - Each time the instrument cluster is put through the actuator test, the brake 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 park brake switch and the brake warning pressure switch are each connected in parallel between ground and the red brake warning indicator driver input to the instrument cluster so that each of their inputs will illuminate the indicator independently of the other. The park brake switch and brake warning indicator switch inputs to the instrument cluster can be diagnosed using conventional diagnostic tools and methods. For proper diagnosis of the PCM, the PCI data bus, or the message inputs to the instrument cluster that control the brake indicator, a DRBIII scan tool is required. Refer to the appropriate diagnostic information.
CHECK GAUGES INDICATOR
A check gauges indicator is standard equipment on all instrument clusters. The check gauges indicator is located on the lower edge of the instrument cluster overlay, to the right of the odometer/trip odometer Vacuum-Fluorescent Display (VFD). The check gauges indicator consists of a stencil-like cutout of the words "CHECK GAUGES" 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 "CHECK GAUGES" text 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 check gauges indicator is serviced as a unit with the instrument cluster.
The check gauges indicator gives an indication to the vehicle operator when certain instrument cluster gauge readings reflect a condition requiring immediate attention. This indicator is controlled by a transistor on the instrument cluster electronic 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 check gauges 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 ground path by the instrument cluster transistor.
The instrument cluster will turn ON the check gauges indicator for the following reasons:
* Bulb Test - Each time the ignition switch is turned to the ON position the check gauges indicator is illuminated for about two seconds as a bulb test.
* Engine Temperature High Message - Each time the cluster receives a message from the PCM indicating the engine coolant temperature is about 127 °C or higher (about 261 °F or higher), the check gauges indicator will be illuminated. The indicator remains illuminated until the cluster receives a message from the PCM indicating that the engine temperature is about 124 °C or lower (about 255 °F or lower), or until the ignition switch is turned to the OFF position, whichever occurs first.
* Engine Oil Pressure Low Message - Each time the cluster receives a message from the PCM indicating the engine oil pressure is about 0.3 kg/cm or lower (about 4 psi or lower), the check gauges indicator will be illuminated. The indicator remains illuminated until the cluster receives a message from the PCM indicating that the engine oil pressure is about 0.6 kg/cm or higher (about 8 psi or higher), or until the ignition switch is turned to the OFF position, whichever occurs first. The cluster will only turn the indicator on in response to an engine oil pressure low message if the engine speed is 300 rpm or greater.
* Charge Fail Message - Each time the cluster receives a message from the PCM indicating a charge fail condition (system voltage is nine volts or lower), the check gauges indicator will be illuminated. The indicator remains illuminated until the cluster receives a message from the PCM indicating there is no charge fail condition (system voltage twelve volts or higher, but lower than sixteen volts) or until the ignition switch is turned to the Off position, whichever occurs first.
* Voltage High Message - Each time the cluster receives a message from the PCM indicating a voltage high condition (system voltage is sixteen volts or higher), the check gauges indicator will be illuminated. The indicator remains illuminated until the cluster receives a message from the PCM indicating there is no voltage high condition (system voltage is sixteen volts or lower, but higher than nine volts) 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 check gauges indicator will be turned ON, then OFF again during the bulb check portion of the test in order to confirm the functionality of the LED and the cluster control circuitry The PCM continually monitors the engine temperature, oil pressure, and electrical system voltage, then sends the proper messages to the instrument cluster. For proper diagnosis of the PCM, the PCI data bus, or the message inputs to the instrument cluster that control the check gauges indicator, a DRBIII scan tool is required. Refer to the appropriate diagnostic information.