The instrument cluster contains the necessary hardware and software to serve as the vehicle's electronic body control module and is commonly referred to as the Cab Compartment Node (CCN). The following information deals primarily with the instrument cluster functions of this unit. Additional details of the electronic body control functions may be found within the service information for the system or component that the CCN controls. For example, additional details of the audible warning functions of the CCN are found within the CHIME/BUZZER - SERVICE INFORMATION .

The CCN is designed to allow the vehicle operator to monitor the conditions of many of the vehicle components and operating systems. The gauges and indicators in the CCN provide valuable information about the various standard and optional powertrains, fuel and emissions systems, cooling systems, lighting systems, safety systems and many other convenience items. The CCN is installed in the instrument panel so that the operator of the vehicle can view all of these monitors easily, yet still allow relative ease of access for service.

The microprocessor-based CCN hardware and software uses various inputs to control the gauges and indicators visible on the face of the cluster. Some of these inputs are hard wired, but most are in the form of electronic messages that are transmitted by other electronic modules over the Controller Area Network (CAN) data bus and the Local Interconnect Network (LIN) data bus. The CCN is the master of the LIN bus. These four modules talk to the CCN: The Heated Seat Module (HSM); the Remote Compass Module (RCM); the Steering Control Module (SCM); and the Accessory Switch Bank Module (ASBM).

The CCN microprocessor smooths the input data using algorithms to provide gauge readings that are accurate, stable, and responsive to operating conditions. These algorithms are designed to provide gauge readings during normal operation that are consistent with customer expectations. However, when abnormal conditions exist such as high coolant temperature, the algorithm can drive the gauge pointer to an extreme position and the microprocessor can sound a chime through the on-board audible tone transducer to provide distinct visual and audible indications of a problem to the vehicle operator. The CCN may also produce audible warnings for other electronic modules in the vehicle based upon electronic tone request messages received over the CAN/LIN data bus. Each audible warning is intended to provide the vehicle operator with an audible alert to supplement a visual indication.

The CCN circuitry operates on battery current received through a fused B(+) fuse on a non-switched fused B(+) circuit, and on battery current received through a fused ignition switch output (run-start) fuse on a fused ignition switch output (run-start) circuit. This arrangement allows the/CCN to provide some features regardless of the ignition switch position, while other features will operate only with the ignition switch in the On or Start positions. The CCN circuitry is grounded through a ground circuit of the instrument panel wire harness.

The CCN also has a self-diagnostic actuator test capability that tests each of the CAN bus message-controlled functions of the cluster. This test illuminates the appropriate indicators, positions the gauge needles at several predetermined calibration points across the gauge faces, and illuminates all segments of the odometer/trip odometer/gear selector indicator Vacuum-Fluorescent Display (VFD) unit and Electronic Vehicle Information Center (EVIC). The EVIC will display the hardware/software version, and the CAN and LIN Vehicle Maintenance Monitor (VMM) used in the CCN. See Diagnosis and Testing .

The CCN collects data and provides control signals for the following electrical equipment via the CAN data bus:

• Gauges
• Interior lighting controls
• Variable-intensity cluster lighting and illumination of instrument panel mounted equipment
• Vehicle Theft Alarm and Sentry Key Theft Deterrent System
• Power door lock system controls (automatic locking, and Remote Keyless Entry locking and unlocking)
• Headlamp switch actuation signal
• Steering wheel radio actuation signals
• Accessory power delay relay control
• Wiper control
• Turn signal flasher audible click
• Heated seat actuation signal (if equipped)
• UConnect Hands-Free, Voice-Actuated Communication system actuation signal (if equipped)
• Display of the outputs for the HomeLink universal home security system and compass (if equipped)
• Illuminated entry system
• Key-in-ignition warning chime
• Seat belt warning chime and lamp (Including BeltAlert)
• Door ajar warning indicator
• Liftgate/trunk ajar warning indicator
• LIN master module

The CCN also provides the following enhancements to the above features:

• Time-out for interior lamps left on inadvertently
• Driver programmability of the power locks to unlock only the driver's door or all doors with the first actuation of the RKE unlock button
• Ability to program vehicle response to lock and unlock commands from the RKE transmitter
• The improved BeltAlert seatbelt warning indication
• Filtering of input signals to the fuel gauge, temperature gauge, and speedometer to avoid sudden, unexpected pointer movements
• Headlamp control for turning the headlamps on if the windshield wipers are operated in daylight as required by law in some states

• Gauges
• Indicators