Part 1

OPERATION - LHD

INDICATORS

Indicators are located in various positions within the instrument cluster, and are all connected to the Cab Compartment Node (CCN) electronic circuit board. Some indicators operate based upon hard-wired inputs to the CCN, but most are controlled by Controller Area Network (CAN) or Local Interface Network (LIN) data bus messages from other electronic modules in the vehicle. Some are controlled by a combination of hard-wired inputs, electronic messaging and CCN programming. If the CCN loses CAN data bus communication, the CCN circuitry will automatically turn ON the Malfunction Indicator Lamp (MIL) until CAN data bus communication is restored. If the CCN looses CAN data bus communication with the Totally Integrated Power Module (TIPM), all of the modules that are supported by the CAN C data bus will illuminate the appropriate cluster tell tale warnings.

The various CCN indicators are controlled by different strategies; some receive fused ignition switch output from the CCN circuitry and have a switched ground, while others are grounded through the CCN circuitry and have a switched battery feed. However, all indicators are completely controlled by the CCN microprocessor based upon various hard-wired and electronic message inputs. The cruise indicator located within the odometer Vacuum-Florescent Display (VFD) unit is dimmable. All other indicators are illuminated at a fixed intensity, which is not affected by the selected illumination intensity of the CCN general illumination lighting. The illumination intensity of the dimmable indicator is synchronized with that of the general illumination lighting.

In addition, certain indicators in this instrument cluster are automatically or self-configured. This feature allows the configurable indicators to be enabled by the CCN circuitry for compatibility with certain optional equipment. These indicators are enabled or disabled by an electronic configuration message sent to the CCN by the TIPM. The TIPM defaults for the Anti-Lock Brake System (ABS) indicator and airbag indicator are enabled, and these configuration settings must be programmatically disabled in the TIPM using a diagnostic scan tool for vehicles that do not have this equipment. The automatically or self-configured indicators remain latent in each CCN at all times and will be active only when the CCN receives the appropriate CAN or LIN bus message inputs for that optional system or equipment.

Hard-wired circuitry connects the CCN to the electrical system of the vehicle. These hard-wired circuits are integral to several wire harnesses, which are routed throughout the vehicle and retained by many different methods. These circuits may be connected to each other, to the vehicle electrical system and to the CCN through the use of a combination of soldered splices, splice block connectors, and many different types of wire harness terminal connectors and insulators. Refer to the appropriate wiring information. The wiring information includes wiring diagrams, proper wire and connector repair procedures, further details on wire harness routing and retention, as well as pin-out and location views for the various wire harness connectors, splices and grounds.

The hard-wired indicator inputs may be diagnosed using conventional diagnostic tools and procedures. However, the CCN circuitry and electronic CAN or LIN data bus message controlled indicators are diagnosed using the instrument cluster self-test Testing and Inspection. Proper testing of the CAN or LIN data bus and the electronic data bus message inputs to the CCN that control each indicator requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.

ABS INDICATOR

The ABS indicator gives an indication to the vehicle operator when the ABS system, or a circuit or component of the system is ineffective. 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 Controller Antilock Brake (CAB) over the CAN data bus.

The ABS indicator Light Emitting Diode (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. Each time the ignition switch is turned to the ON position the ABS indicator is illuminated for about three seconds as a bulb test. The entire bulb test is a function of the CAB. The instrument cluster will turn ON the ABS indicator for the following reasons:

- ABS Indicator Lamp-On Message - Each time the cluster receives an electronic ABS indicator lamp-ON message from the CAB, the ABS indicator will be illuminated. The indicator remains illuminated until the cluster receives a lamp-OFF message from the CAB, 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 CAB for five consecutive message cycles, the ABS indicator is illuminated. The indicator remains illuminated until the cluster receives a valid message from the CAB, or until the ignition switch is turned to the OFF position, whichever occurs first.
- ABS Diagnostic Test - The ABS indicator is blinked ON and OFF by lamp-ON and lamp-OFF messages from the CAB during the performance of the ABS diagnostic tests.

The CAB continually monitors the ABS circuits and sensors to decide whether the system is in good operating condition. The CAB then sends the proper lamp-ON or lamp-OFF message to the CCN. If the CAB sends a lamp-ON message after the bulb test, it indicates that the CAB has detected a system malfunction or that the ABS system has become ineffective. The CAB will store a Diagnostic Trouble Code (DTC) for any malfunction it detects. Each time the ABS indicator fails to light due to an open or short in the cluster ABS indicator circuit, the cluster sends a message notifying the CAB of the condition, then the instrument cluster and the CAB will each store a DTC and the cluster will flash the brake indicator ON and OFF as a backup to notify the vehicle operator.