Part 6 of 8
HIGH BEAM INDICATORSA high beam indicator is standard equipment on all instrument clusters. The high beam indicator is located near the upper edge of the instrument cluster overlay, between the tachometer and the speedometer. The high beam indicator consists of a stenciled cutout of the International Control and Display Symbol icon for "High Beam" 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 blue lens behind the cutout in the opaque layer of the overlay causes the icon to appear in blue when it is illuminated from behind by a replaceable incandescent bulb and bulb holder unit located on the instrument cluster electronic circuit board. The high beam indicator is serviced as a unit with the instrument cluster.
The high beam indicator gives an indication to the vehicle operator when the headlamp high beams are illuminated. This indicator is hard wired on the instrument cluster electronic circuit board, and is controlled by the Central Timer Module (CTM) through the high beam indicator driver circuit input to the cluster based upon a control signal to the CTM from the headlamp beam select switch. The headlamp beam select switch is integral to the multi-function switch on the left side of the steering column. The high beam indicator bulb receives battery current on the instrument cluster electronic circuit board through a fused B(+) circuit at all times; therefore, the indicator remains operational regardless of the ignition switch position. The indicator only illuminates when it is provided with a path to ground by the CTM. The high beam indicator can be diagnosed using conventional diagnostic tools and methods. For proper diagnosis of the CTM and the inputs to the CTM that control the high beam indicator driver circuit, 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 stenciled 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 lens 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 the indicator is illuminated from behind by a Light Emitting Diode (LED) 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) 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 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 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 INSTRUMENT CLUSTER - DIAGNOSIS AND TESTING). For proper diagnosis of the liftgate ajar switch and circuits, (Refer to LIFTGATE AJAR SWITCH - DIAGNOSIS AND TESTING). For proper diagnosis of the CTM, the PCI data bus, or the message inputs to the instrument cluster that control the liftgate ajar indicator, a DRB III scan tool is required. Refer to the appropriate diagnostic information.
LOW FUEL INDICATOR
A low fuel indicator is standard equipment on all instrument clusters. The low fuel indicator is located in the Information Center area of the instrument cluster overlay, to the left of center. The low fuel indicator consists of a stenciled cutout of the International Control and Display Symbol icon for "Fuel" 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 the indicator is illuminated from behind by a Light Emitting Diode (LED) soldered onto the instrument cluster electronic circuit board. The low fuel indicator is serviced as a unit with the instrument cluster.
The low fuel indicator gives an indication to the vehicle operator when the level of fuel in the fuel tank becomes low. 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 Powertrain Control Module (PCM) over the Programmable Communications Interface (PCI) data bus. The low fuel 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 low fuel indicator for the following reasons:
- Bulb Test - Each time the ignition switch is turned to the ON position the indicator is illuminated for about two seconds as a bulb test.
- Less Than 12.5 Percent Tank Full Message - Each time the cluster receives messages from the PCM indicating the percent tank full is 12.5 (one-eighth) or less for 10 consecutive seconds and the vehicle speed is zero, or for 60 consecutive seconds and the vehicle speed is greater than zero the low fuel indicator is illuminated and a single chime tone is sounded. The low fuel indicator remains illuminated until the cluster receives messages from the PCM indicating that the percent tank full is greater than 12.5 (one-eighth) for 10 consecutive seconds and the vehicle speed is zero, or for 60 consecutive seconds and the vehicle speed is greater than zero, or until the ignition switch is turned to the OFF position, whichever occurs first. The chime tone feature will only repeat during the same ignition cycle if the low fuel indicator is cycled OFF and then ON again by the appropriate percent tank full messages from the PCM.
- Less Than Empty Percent Tank Full Message - Each time the cluster receives a message from the PCM indicating the percent tank full is less than empty, the low fuel indicator is illuminated immediately. This message would indicate that the fuel tank sender input to the PCM is a short circuit.
- More Than Full Percent Tank Full Message - Each time the cluster receives a message from the PCM indicating the percent tank full is more than full, the low fuel indicator is illuminated immediately. This message would indicate that the fuel tank sender input to the PCM is an open circuit.
- 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 PCM continually monitors the fuel tank sending unit, then sends the proper messages to the instrument cluster. For further diagnosis of the low fuel indicator or the instrument cluster circuitry that controls the LED, (Refer to INSTRUMENT CLUSTER - DIAGNOSIS AND TESTING). For proper diagnosis of the fuel tank sending unit, the PCM, the PCI data bus, or the message inputs to the instrument cluster that control the low fuel indicator, a DRB III scan tool is required. Refer to the appropriate diagnostic information.