Part 3
OPERATION
POSITION LAMP INDICATOR
The position lamp indicator gives an indication to the vehicle operator whenever the position lamps (exterior lighting) are illuminated. 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 TIPM over the CAN data bus.
The position lamp indicator LED is completely controlled by the instrument cluster logic circuit, and that logic will allow this indicator to operate whenever the instrument cluster receives a battery current input on the fused B(+) circuit. Therefore, the LED can be illuminated regardless of the ignition switch position. The LED only illuminates when it is provided a path to ground by the instrument cluster transistor. The instrument cluster will turn ON the position lamp indicator for the following reasons:
- Position Lamp Indicator Lamp-On Message - Each time the cluster receives an electronic position lamp indicator lamp-ON message from the TIPM indicating the position lamps are turned ON, the position lamp indicator will be illuminated. The indicator remains illuminated until the cluster receives a lamp-OFF message from the TIPM, or until the exterior lamp load shedding (battery saver) timed interval expires, whichever occurs first.
The TIPM continually monitors electronic exterior lighting switch request messages from the CCN to determine the appropriate outputs to the park lamp relay. The TIPM activates or deactivates the park lamp relay then sends the proper lamp-ON or lamp-OFF message back to the CCN.
SEAT BELT INDICATOR
The seat belt indicator gives an indication to the vehicle operator of the status of the driver side front seat belt. This indicator is controlled by a transistor on the CCN circuit board based upon cluster programming and a hard wired input from the seat belt switch in the driver side front seat belt retractor through the seat belt indicator driver circuit.
The seat belt indicator also includes a programmable enhanced seat belt reminder or "beltminder" feature that is enabled when the vehicle is shipped from the factory. This beltminder feature can be disabled and enabled by the customer using a specific programming event sequence, or by the dealer using a diagnostic scan tool.
The seat belt indicator LED 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 ignition switch output (run-start) circuit. 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 CCN transistor. The CCN will turn on the seat belt indicator for the following reasons:
- Seat Belt Reminder Function - Each time the CCN receives a battery current input on the fused ignition switch output (run-start) circuit, the indicator will be illuminated as a seat belt reminder for about six 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 seat belt switch input to the cluster.
- Driver Side Front Seat Belt Not Buckled - Beltminder Active - Following the seat belt reminder function, each time the CCN detects an open circuit on the seat belt indicator driver circuit (seat belt switch open = seat belt unbuckled) with the ignition switch in the START or ON positions, the indicator will be illuminated. In addition, if the driver side front seat belt remains unbuckled after the conclusion of the seat belt reminder function, with the vehicle speed greater than about5 MPH (8 Kph), the seat belt indicator will begin to cycle between flashing on and off for three seconds, then lighting solid for two seconds. The seat belt indicator will continue to cycle between flashing and solid illumination for thirteen complete cycles, until the seat belt indicator driver input to the cluster is closed to ground (seat belt switch closed = seat belt buckled), or until the ignition switch is turned to the OFF position, whichever occurs first.
- Driver Side Front Seat Belt Not Buckled - Beltminder Inactive - Following the seat belt reminder function, each time the cluster detects an open circuit on the seat belt indicator driver circuit (seat belt switch open = seat belt unbuckled) with the ignition switch in the START or ON positions, the indicator will be illuminated. The seat belt indicator remains illuminated until the seat belt indicator driver input to the cluster is closed to ground (seat belt switch closed = seat belt buckled), or until the ignition switch is turned to the OFF position, whichever occurs first.
The seat belt switch is connected in series between ground and the seat belt indicator driver input to the instrument cluster. The seat belt switch input to the instrument cluster circuitry may be diagnosed using conventional diagnostic tools and methods. Refer to the appropriate wiring information.
SECURITY INDICATOR
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 transistor on the CCN circuit board based upon programming, hard wired inputs to the CCN from the various security system components, electronic messages received from the WIN over the CAN data bus. The CCN will illuminate the security indicator for about three seconds each time the ignition is turned to the ON position, during the bulb test.
The security indicator LED is completely controlled by the instrument cluster logic circuit, and that logic will allow this indicator to operate whenever the instrument cluster receives a battery current input on the fused B(+) circuit. Therefore, the LED can be illuminated regardless of the ignition switch position. The LED only illuminates when it is provided a path to ground by the CCN transistor. The CCN will also turn on the security indicator for the following reasons:
- VTSS Indication - During the sixteen second VTSS arming function, the cluster 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 cluster 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 has alarmed and rearmed, the cluster will flash the security indicator at a steady, slow rate for about thirty seconds after the VTSS is disarmed.
- SKIS Lamp-ON Message - Each time the CCN receives a SKIS lamp-on message from the WIN, the security indicator will be illuminated. The indicator can be flashed on and off, or illuminated solid, as dictated by the WIN message. The indicator remains illuminated solid or continues to flash until the CCN receives a SKIS lamp-off message from the WIN, 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, Vehicle Theft Security System - Operation.
- Communication Error - If the CCN receives no SKIS lamp-on or lamp-off messages from the WIN for ten consecutive message cycles, the security indicator is illuminated by the CCN. The indicator remains controlled and illuminated by the CCN until a valid SKIS lamp-on or lamp-off message is received.
The CCN circuitry controls the security indicator whenever the ignition switch is in the OFF position and the VTSS is arming, armed, or alarming. Whenever the ignition switch is in the ON or START positions, the WIN performs a self-test to decide whether the SKIS is in good operating condition and whether a valid key is present in the ignition lock cylinder. The WIN then sends the proper lamp-on or lamp-off messages to the CCN. If the instrument cluster flashes the security indicator upon ignition ON, or turns on the security indicator solid after the bulb test, it indicates that a SKIS malfunction has occurred or that the SKIS is inoperative.
SERVICE 4WD INDICATOR
The service 4WD indicator gives an indication to the vehicle operator when the TIPM 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 over the CAN data bus. The CCN will illuminate the service 4WD indicator for about two seconds each time the ignition is turned to the ON position, during the bulb test.
The service 4WD indicator LED 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 ignition switch output (run-start) circuit. 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:
- Service 4WD Indicator Lamp-On Message - Each time the cluster receives an electronic service 4WD indicator lamp-ON message from the TIPM, the service 4WD indicator will be illuminated. The indicator remains illuminated until the cluster receives a lamp-OFF message from the TIPM, or until the ignition switch is turned to the OFF position, whichever occurs first.
- Communication Error - If the cluster receives no lamp-ON or lamp-OFF messages from the TIPM for 10 seconds, the service 4WD indicator is illuminated by the cluster to indicate a loss of TIPM communication. The indicator remains controlled and illuminated by the cluster until a valid message is received from the TIPM.
The TIPM continually monitors the electronic transfer case control circuits and transfer case shift motor/mode sensor assembly to determine the condition of the system. The TIPM then sends the proper lamp-ON or lamp-OFF message to the CCN.
TOW/HAUL INDICATOR
The tow/haul indicator gives an indication to the vehicle operator when the tow/haul function switch has been selected, revising the shift schedule of the electronically controlled automatic transmission. 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 PCM over the CAN data bus.
The tow/haul indicator LED is completely controlled by the instrument cluster logic circuit. This logic only allows the indicator to operate when the instrument cluster receives a battery current input on the fused ignition switch output (run-start) circuit. Therefore, the LED is always 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 turns on the tow/haul indicator for the following reasons:
- Tow/Haul Indicator Lamp-On Message - Each time the cluster receives an electronic tow/haul indicator lamp-on message from the PCM indicating that the tow/haul shift schedule has been selected, the indicator illuminates. The indicator remains illuminated until the cluster receives a lamp-off message from the PCM, or until the ignition switch is turned to the OFF position, whichever occurs first.
The PCM continually monitors the tow/haul switch to determine the proper outputs to the automatic transmission. The PCM then sends the proper lamp-on or lamp-off message to the instrument cluster, also known as the CCN.
TRACTION CONTROL INDICATOR
The traction control indicator gives an indication to the vehicle operator when the electronic Traction Control System (TCS) has been activated. This indicator is controlled by the CCN circuit board based upon programming and electronic messages received from the CAB over the CAN data bus. The CCN will illuminate the traction control indicator for about four seconds each time the ignition is turned to the ON position, during the bulb test.
The traction control indicator 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 ignition switch output (run-start) circuit. 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 traction control indicator for the following reasons:
- Traction Control Lamp-ON Message - Each time the CCN receives a traction control lamp-ON message from the CAB indicating that the TCS has been activated, the traction control indicator will be illuminated. The indicator remains illuminated until a traction control lamp-off message from the CAB is received, or until the ignition switch is turned to the OFF position, whichever occurs first.
The CAB continually monitors the traction control switch to determine the proper outputs to the components of the ABS. The CAB then sends the proper traction control lamp-on and lamp-OFF messages to the CCN.
TRANSMISSION RANGE INDICATOR
The electronic gear selector indicator gives an indication to the vehicle operator of the transmission gear that has been selected with the automatic transmission gear selector lever. This indicator is controlled by the instrument cluster circuit board based upon cluster programming and electronic messages received from the Powertrain Control Module (PCM) over the Controller Area Network (CAN) data bus.
The gear selector indicator information is displayed by the odometer Vacuum Fluorescent Display (VFD) unit soldered onto the instrument cluster electronic circuit board, and the VFD will not display the gear selector indicator information after the ignition switch is turned to the OFF position. Each time the cluster is disconnected from battery current for more than about five minutes, it must configure itself for the automatic transmission type that is in the vehicle once it is reconnected to battery current. The instrument cluster circuitry operates the gear selector indicator to provide the following features:
- Selected Gear Message - Each time the cluster receives an electronic selected gear message from the PCM, a box will be illuminated around the appropriate character in the gear selector indicator. The box will remain illuminated until the cluster receives a different selected gear message, or until the ignition switch is turned to the OFF position, whichever occurs first.
- Communication Error - If the cluster fails to receive a selected gear message from the PCM within three seconds, the instrument cluster circuitry will display all gear selector positions boxed (selected) until a valid selected gear message is received or until the ignition switch is turned to the OFF position, whichever occurs first.
The PCM continually monitors a hard wired multiplex input from the Transmission Range Sensor (TRS), then sends the proper message to the CCN.
TRANSMISSION TEMPERATURE INDICATOR
The transmission over-temperature indicator gives an indication to the vehicle operator when the transmission fluid temperature is excessive, which may lead to accelerated transmission component wear or failure. 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 PCM over the CAN data bus. The CCN will illuminate the traction control indicator for about two seconds each time the ignition is turned to the ON position, during the bulb test.
The transmission over-temperature indicator LED is completely controlled by the instrument cluster logic circuit. This logic only allows the indicator to operate when the instrument cluster receives a battery current input on the fused ignition switch output (run-start) circuit. Therefore, the LED is always 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 turns on the transmission over-temperature indicator for the following reasons:
- Trans Over-Temp Indicator Lamp-On Message - Each time the cluster receives an electronic transmission over temp indicator lamp-on message from the PCM indicating that the transmission fluid temperature is 275°F (135 °C ) or higher, the indicator illuminates and a single chime tone is sounded. The indicator remains illuminated until the cluster receives a lamp-off message from the PCM, or until the ignition switch is turned to the OFF position, whichever occurs first. The chime tone feature only repeats during the same ignition cycle if the indicator is cycled off and then on again by the appropriate lamp-on and lamp-off messages from the PCM.
The PCM continually monitors the transmission temperature sensor to determine the transmission operating condition. The PCM then sends the proper lamp-on or lamp-off message to the CCN. If the transmission over temperature indicator is illuminated due to a high transmission oil temperature condition, it may indicate that the transmission or the transmission cooling system are being overloaded, or that they require service.
TURN SIGNAL INDICATORS
The turn signal indicators give an indication to the vehicle operator that the turn signal (left or right indicator flashing) or hazard warning (both left and right indicators flashing) have been selected and are operating. These indicators are controlled by transistors on the CCN electronic circuit board based upon the cluster programming, a hard wired multiplex input received by the cluster from the turn signal and hazard warning switch circuitry of the multi-function switch on the turn/hazard switch mux circuit, and electronic messages received from the TIPM over the CAN data bus.
Each turn signal indicator LED is completely controlled by the instrument cluster logic circuit, and that logic will allow this indicator to operate whenever the instrument cluster receives a battery current input on the fused B(+) circuit. Therefore, each LED can be illuminated regardless of the ignition switch position. The LED only illuminates when it is provided a path to ground by the CCN transistor. The CCN will turn on the turn signal indicators for the following reasons:
- Turn Signal-ON Input - The Steering Control Module (SCM) sends a Data Bus message to the TIPM to turn on the turn signals. The TIPM also sends out a message to the CCN to illuminate the appropriate electronic turn signal switch indicator. The TIPM controls the output and the flash rate for either the right or left turn signal lamps and sends this message to the CCN. The CCN will then control the illumination and flash rate of the right or left turn signal indicators, as well as to control the click rate of an electromechanical relay soldered onto the CCN electronic circuit board that emulates the sound emitted by a conventional turn signal flasher. The turn signals and the turn signal indicators continue to flash on and off until the cluster receives a turn signal-off input from the multi-function switch, or until the ignition switch is turned to the OFF position, whichever occurs first.
- Hazard Warning-ON Input - The turn signal flashers are also controlled by the TIPM. The SCM sends a Data Bus message to the TIPM and the TIPM responds to these messages by controlling a battery voltage output and the flash rate for each of the right and left turn signal lamps. The TIPM also sends the appropriate electronic messages back to the CCN to control the illumination and flash rate of the right and left turn signal indicators, as well as to control the click rate of an electromechanical relay soldered onto the CCN electronic circuit board that emulates the sound emitted by a conventional hazard warning flasher. The turn signals and the turn signal indicators continue to flash on and off until the cluster receives a hazard warning-off input from the multi-function switch.
- Lamp Out Mode - The CCN also sends electronic turn signal on and off messages to the TIPM over the CAN data bus, and the TIPM flashes the appropriate exterior turn signal lamps. If the TIPM detects an inoperative turn signal lamp or circuit, it increases the flash rate for the remaining operative turn signals and sends an electronic message back to the instrument cluster. The instrument cluster then increases the flash rate of the turn signal indicator(s) and the clicking rate of the electromechanical relay to provide an indication of the problem to the vehicle operator.
The CCN continually monitors the multi-function switch and electronic messages from the TIPM to determine the proper turn signal and hazard warning system control.
WAIT-TO-START INDICATOR
The wait-to-start indicator gives an indication to the vehicle operator when the diesel engine is too cool for efficient and reliable engine starting, and the engine glow plugs are energized in their pre-heat operating mode. This indicator is controlled by a transistor on the CCN circuit board based upon programming and electronic messages received from the PCM over the CAN data bus.
The wait-to-start indicator LED 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 ignition switch output (run-start) circuit. 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 CCN transistor. The CCN will illuminate the wait-to-start indicator for the following reasons:
- Wait-To-START Indicator Lamp-ON Message - Each time the CCN receives an electronic wait-to-start indicator lamp-ON message from the PCM indicating that the air temperature is too cool for efficient and reliable engine starting and the glow plugs are energized in their pre-heat mode, the wait-to-start indicator will be illuminated. The indicator remains illuminated until the cluster receives a lamp-OFF message from the PCM, until the PCM detects that the engine is running, or until the ignition switch is turned to the OFF position, whichever occurs first.
The PCM continually monitors the glow plug control circuits to determine when they are energized in their pre-heat operating mode. The PCM then sends the proper lamp-ON or lamp-OFF message to the CCN.
WATER IN FUEL INDICATOR
The water-in-fuel indicator gives an indication to the vehicle operator when there is excessive water detected in the diesel fuel. This indicator is controlled by the CCN based upon programming and electronic messages received from the PCM over the CAN data bus.
The water-in-fuel indicator LED is completely controlled by the 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 ignition switch output (run-start) circuit. 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 CCN transistor. The CCN will illuminate the water-in-fuel indicator for the following reasons:
- Water-In-Fuel Indicator Lamp-ON Message - Each time the CCN receives an electronic water-in-fuel indicator lamp-ON message from the PCM indicating there is excessive water in the diesel fuel system, the water-in-fuel indicator will be illuminated. The indicator remains illuminated until the cluster receives a lamp-OFF message from the PCM, or until the ignition switch is turned to the OFF position, whichever occurs first.
The PCM continually monitors the water-in-fuel sensor to determine whether there is excessive water in the diesel fuel system. The PCM then sends the proper electronic water-in-fuel message to the CCN.