Part 6

OPERATION - LHD

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 Transmission Control Module (TCM), over the CAN data bus.

The gear selector indicator information is displayed by the odometer 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 TCM, 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/ECM 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 TCM continually monitors a hard-wired multiplex input from the Transmission Range Sensor (TRS), then sends the proper message to the CCN.

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 instrument cluster circuit board based upon cluster programming and electronic messages received by the cluster from the ECM 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 instrument cluster transistor. The instrument cluster will turn ON the wait-to-start indicator for the following reasons:

- Wait-To-Start Indicator Lamp-On Message - Each time the cluster receives an electronic wait-to-start indicator lamp-ON message from the ECM 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 ECM, until the ECM detects that the engine is running, or until the ignition switch is turned to the OFF position, whichever occurs first.

The ECM continually monitors the glow plug control circuits to determine when they are energized in their pre-heat operating mode. The ECM 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.

WASHER FLUID INDICATOR

The washer fluid indicator gives an indication to the vehicle operator that the fluid level in the washer reservoir is low. This indicator is controlled by the instrument cluster logic circuit based upon cluster programming and electronic messages received by the cluster from the TIPM over the CAN data bus.

The washer fluid indicator function of the odometer or EVIC VFD 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 ignition switch output (run-start) circuit. Therefore, the odometer or EVIC VFD washer fluid indication will always be OFF when the ignition switch is in any position except ON or START. The instrument cluster will turn ON the washer fluid indicator for the following reasons:

- Washer Fluid Indicator Lamp-On Message - Each time the cluster receives an electronic washer fluid indicator lamp-ON message from the TIPM indicating that a low washer condition has been detected for 60 consecutive seconds, the washer fluid indicator is illuminated and a single chime tone is sounded. The indicator remains illuminated until the cluster receives lamp-OFF messages for 60 consecutive seconds from the TIPM, 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 washer fluid indicator is cycled OFF and then ON again by the appropriate lamp-ON and lamp-OFF messages from the TIPM.

The TIPM continually monitors the washer fluid level switch in the washer reservoir to determine the level of the washer fluid. The TIPM then sends the proper lamp-ON or lamp-OFF message to the CCN.

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 instrument cluster electronic circuit board based upon the cluster programming 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 instrument cluster transistor. The instrument cluster will turn ON the turn signal indicators for the following reasons:

- Turn Signal Indicator Lamp-On Message - The CCN receives an electronic right or left turn signal-ON message from the multifunction switch over the over the LIN data bus. The CCN in turn will transmit the request across the BUS to the TIPM and the appropriate turn signal indicator will be flashed ON and OFF. The TIPM will then send the appropriate electronic message to the cluster to control the flash rate of the turn signal indicators, as well as to control the click rate of an electromechanical relay soldered onto the cluster electronic circuit board that emulates the sound emitted by a conventional turn signal flasher. The turn signal indicators continue to flash ON and OFF 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.
- Hazard Warning Indicator Lamp-On Message - The CCN receives an electronic hazard warning-ON message from the multifunction switch across the LIN data bus. The CCN will transmit this request to the TIPM and the TIPM then sends the appropriate electronic messages to the cluster to control the 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 cluster electronic circuit board that emulates the sound emitted by a conventional hazard warning flasher. The turn signal indicators continue to flash ON and OFF until the cluster receives a hazard warning-OFF message from the TIPM.
- Lamp Out Mode - If the TIPM detects an ineffective turn signal lamp or circuit, it increases the flash rate for the remaining operative turn signals and sends an electronic message to the instrument cluster. The instrument cluster then increases the flash rate of the turn signal indicators and the click rate of the electromechanical relay to provide an indication of the problem to the vehicle operator.

The CCN continually monitors the electronic messages from the TIPM to determine the proper turn signal and hazard warning indicator operation.