Instrument Cluster - Description
DESCRIPTION
The instrument cluster (3) is located in the instrument panel above the steering column opening, directly in front of the driver. The main body of the instrument cluster, including the mounts and the electrical connections, are concealed within the instrument panel below the instrument panel top over (2). The instrument cluster includes the hardware and software necessary to serve as the electronic body control module and is also known as the Cab Compartment Node or (CCN).
Besides analog gauges and indicators, the CCN module incorporates one standard and one optional blue-green digital Vacuum Fluorescent Display (VFD) units. The standard VFD is a fixed segment unit for displaying odometer information, automatic transmission gear selector position (PRNDL), and several other indicators. The optional VFD is a large, reconfigurable display unit which serves as the visual display for the compass, the outside temperature, the trip computer, and the audio system settings as well as the user interface for the customer programmable features, numerous textual warning or reminder indicators and certain diagnostic information.
The instrument cluster gauges and Light Emitting Diode (LED) indicators are visible through a dedicated opening in the instrument panel below the cluster hood and are protected by a clear plastic cluster lens (3). Nine integral latch formations on the lens secure it to the cluster hood and mask unit (2) as well as the cluster housing (1). Just behind the cluster lens is the cluster hood and integral mask, which are constructed of molded black plastic. The hood serves as a visor and shields the face of the cluster from ambient light and reflections to reduce glare, while the cluster mask serves to separate and define the individual gauges from the indicator areas and trims the outside perimeter of the cluster overlay. The hood and mask has six integral latch features that secure it to the outer perimeter of the cluster housing. The hood and mask unit also has two integral mounting tabs on the lower corners that combine with the tabs integral to the cluster housing to secure the bottom of the CCN to the molded plastic instrument panel cluster carrier with two screws.
The rear of the cluster housing and the CCN electronic circuitry are protected by a molded white plastic rear cover (5), which is also secured to the cluster housing by integral latch features. The rear cover includes clearance holes for the four cluster connector receptacles. The connector receptacles on the back of the cluster electronic circuit board connect the CCN to the vehicle electrical system through four take outs with connectors from the instrument panel wire harness.
Sandwiched between the rear cover and the lens and hood unit is the cluster housing. The molded white plastic cluster housing serves as the carrier for the cluster circuit board and circuitry, the cluster connector receptacles, the two major and two minor gauges, a LED's for each cluster indicator, the VFD display units, an audible tone transducer, several LED units for general cluster illumination, the cluster overlay, and the gauge pointers. The standard equipment molded black plastic odometer/trip odometer switch button as well as the optional reconfigurable display switch button (4) extend from the face of the cluster housing through dedicated holes in the cluster mask and the cluster lens adjacent to their respective VFD units. The cluster housing also has four integral mounting tabs, one on each upper and lower corner of the housing.
The cluster overlay is a laminated plastic unit. The dark, visible, outer surface of the overlay is marked with all of the gauge dial faces and graduations, but this layer is also translucent. The darkness of this outer layer prevents the cluster from appearing cluttered or busy by concealing the cluster indicators that are not illuminated, while the translucence of this layer allows those indicators and icons that are illuminated to be readily visible. The underlying layer of the overlay is opaque and allows light from the LED for each of the various indicators and illumination lamps behind it to be visible through the outer layer of the overlay through predetermined stencil-like cutouts. Openings in the overlay at the base of the speedometer and tachometer dial faces have smoked clear lenses through which the illuminated VFD units can be viewed.
Several versions of the CCN module are offered on this vehicle. These versions accommodate all of the variations of optional equipment and regulatory requirements for the various markets in which the vehicle is offered. The microprocessor-based CCN utilizes integrated circuitry and information carried on the Controller Area Network (CAN) data bus and the Local Interface Network (LIN) data bus along with several hard wired analog and multiplexed inputs to monitor sensors and switches throughout the vehicle. In response to those inputs, the internal circuitry and programming of the CCN allow it to control and integrate many electronic functions and features of the vehicle through both hard wired outputs and the transmission of electronic message outputs to other electronic modules in the vehicle over the CAN and LIN data busses. Communication - Description.
VEHICLE SYSTEMS SUPPORT
Besides typical instrument cluster gauge and indicator support, the electronic functions and features that the CCN supports or controls include the following:
- A/C Select and Evaporator Probe Support - The CCN monitors hard wired inputs from the A/C select switch in the air conditioner-heater control and evaporator temperature sensor inputs, then transmits electronic A/C clutch request messages over the CAN data bus when appropriate to support the A/C clutch control feature.
- Audible Warnings - The CCN electronic circuit board is equipped with an audible tone transducer and programming that allows it to provide various audible alerts to the vehicle operator. These alerts include single chime tones and continuous slow or fast tones. An electromechanical relay is also soldered onto the circuit board to produce audible clicks that are used to emulate the sound of a conventional turn signal or hazard warning flasher.
- Electric Backlight Support - The CCN monitors Electric BackLight (EBL) switch hard wired inputs from the air conditioner-heater control, then transmits the appropriate electronic EBL request messages over the CAN data bus to support the EBL function.
- Enhanced Accident Response Support - The CCN monitors an input from the Occupant Restraint Controller (ORC) and, following an airbag deployment, will immediately disable the power lock output, unlock all doors by activating the power unlock output, then enables the power lock output if the power lock switch input remains inactive for two seconds. The CCN also monitors an input from the Powertrain Control Module (PCM) to automatically turn ON the interior lighting after an airbag deployment event, 10 seconds after the vehicle speed is zero. The interior lighting remains illuminated until the key is removed from the ignition switch lock cylinder, at which time the interior lighting returns to normal operation and control. These Enhanced Accident Response System (EARS) features are each dependent upon a functional vehicle electrical system following the vehicle impact event.
- Exterior Lighting Switch Support - The CCN monitors electronic exterior lighting switch, and turn signal switch status messages from the Steering Control Module (SCM) on the steering column over the LIN data bus and transmits the appropriate electronic exterior lighting and turn signal request messages to the Totally Integrated Power Module (TIPM) over the CAN data bus to support the exterior lighting functions.
- Four Wheel Drive (4WD) Lock Switch Support - The CCN monitors a hard wired input from the 4WD Lock switch on the center floor console then transmits the appropriate electronic 4WD Lock request and Unlock request messages to the All Wheel Drive Control Module (AWDCM) over the CAN data bus to support the 4WD Lock mode functions.
- Fuel Level Data Support - The CCN provides a current source for and receives a hard wired analog input from the fuel level sending unit located on the fuel pump module in the fuel tank. The CCN uses this input to calculate the proper fuel gauge needle position and to control low fuel indicator operation. Based upon this input, the CCN also uses electronic messaging to transmit this data over the CAN data bus for use by other electronic modules in the vehicle.
- Hazard Switch Support - The CCN monitors electronic hazard switch status messages from the instrument panel switch pod on the instrument panel over the LIN data bus and transmits the appropriate electronic hazard lamp request messages to the Totally Integrated Power Module (TIPM) over the CAN data bus to support the hazard lamps function.
- Heated Seat Switch Support - On vehicles equipped with optional heated seats, the CCN monitors electronic heated seat switch status messages from the heated seat switches in the instrument panel switch pod and transmits electronic heated seat request messages to the Heated Seat Module (HSM) over the LIN data bus. This message wakes up the HSM when the switch is actuated.
- Horn Switch Support - The CCN receives a hard wired input from the horn switch on the steering wheel then provides electronic horn request messages over the CAN data bus to support the horn function.
- Interior Lamp Load Shedding - The CCN provides a battery saver feature which will automatically turn OFF all interior lamps if they remain ON after a timed interval of about ten minutes.
- Interior Lighting Control - The CCN monitors electronic messages and hard wired inputs from the interior lighting switch, the door ajar switches, the liftgate ajar switch, the reading lamp switches, and the Sentry Key REmote Entry Module (SKREEM) (also known as the Wireless Control Module/WCM) to provide courtesy lamp control. This includes support for timed illuminated entry with theater-style fade-to-OFF and courtesy illumination DEFEAT features.
- Local Interface Network Master Module - The CCN is the master module for the LIN data bus. In this role it gathers information from the compass sensor, the Heated Seat Module (HSM), the instrument panel switch pod and the SCM, then either acts on that information directly or places electronic messages on the CAN data bus for use by other modules
- Panel Lamps Dimming Control - The CCN monitors electronic dimming level messages received from the panel lamps dimmer switch input to the SCM over the LIN data bus, then provides both a hard wired 12-volt Pulse-Width Modulated (PWM) output and electronic message outputs over the LIN data bus that synchronizes the dimming level of all panel lamps dimmer controlled lamps with that of the cluster general illumination lighting.
- Power Lock System Control - The CCN monitors inputs from the power lock switches and the SKREEM (also known as the Wireless Control Module/WCM) to provide control of the power lock motors through high side and low side driver outputs. This includes support for rolling door locks (also known as automatic door locks), automatic door unlock, and a door lock inhibit mode.
- Reconfigurable Display Support - The CCN provides support for each of the functions and features of the reconfigurable display. This includes support for the compass, thermometer, audio system mode, customer programmable features, textual warnings, premium Tire Pressure Monitor (TPM), trip computer, U-Connect(TM) Hands-Free communication, HomeLink(TM) Universal Garage Door Opener (UGDO) and the reconfigurable display switch inputs that are used to control and configure many of the displays. This also includes display arbitrator programming, which controls the priorities, sequences, and transition of information that is displayed in the reconfigurable display, particularly when multiple display requests are received simultaneously.
- Remote Keyless Entry Support - The CCN supports the Remote Keyless Entry (RKE) system features, including support for the RKE LOCK, UNLOCK (with optional driver-door-only unlock, and unlock-all-doors), PANIC, audible chirp, optical chirp, illuminated entry modes, an RKE programming mode, as well as optional Vehicle Theft Security System (VTSS) arming (when the proper VTSS arming conditions are met) and disarming.
- Remote Radio Switch Support - The CCN receives a hard wired input from the remote radio switches on the steering wheel then provides electronic radio request messages over the CAN data bus to support the remote radio switch function.
- Vehicle Theft Security System Control - The CCN monitors inputs from the door ajar switches, the SCM, the SKREEM (also known as the Wireless Control Module/WCM) and, on vehicles so equipped, the intrusion module then provides electronic horn and lighting request messages to the TIPM for the appropriate VTSS alarm output features.
- Wiper and Washer Switch Support - The CCN monitors electronic wiper switch and washer switch status messages from the SCM on the steering column over the LIN data bus and transmits the appropriate electronic wiper and washer request messages to the TIPM over the CAN data bus to support the wiper and washer system functions, including the headlamps-on with wipers programmable feature.
VACUUM-FLUORESCENT DISPLAYS
The Vacuum-Fluorescent Display (VFD) (25)(31) units are soldered to the CCN electronic circuit board. Both the standard one located below the tachometer and the optional Compass Mini-Trip Computer (CMTC) display located below the speedometer are fixed segment displays.
An odometer and trip odometer are standard factory-installed equipment in all instrument clusters. The odometer and trip odometer are displayed in a common electronic, blue-green Vacuum-Fluorescent Display (VFD) unit. This VFD unit is soldered onto the cluster electronic circuit board, and is visible through a window with a smoked clear lens located on the lower edge of the tachometer in the lower right area of the cluster overlay. The dark lens over the VFD prevents the indicator from being clearly visible when it is not illuminated.
The odometer and trip odometer information are not displayed simultaneously. The trip odometer reset switch on the instrument cluster circuit board toggles the display between odometer and trip odometer modes by depressing the odometer/trip odometer switch button that extends through the lower edge of the cluster lens, just left of the minor gauge set. When the trip odometer information is displayed, the text TRIP A or TRIP B is also illuminated in the lower right corner of the odometer/trip odometer VFD in a blue-green color and at the same lighting level as the trip odometer information.
The odometer and trip odometer information are stored in the instrument cluster memory. This information can be increased when the proper inputs are provided to the instrument cluster, but the information cannot be decreased. The odometer can display values up to 999,999 kilometers (999,999 miles). The odometer latches at these values, and will not roll over to zero. The trip odometer can display values up to 999.9 kilometers (999.9 miles) before it rolls over to zero.
The odometer display does not show leading zeroes, does not have a decimal point and will not show values less than a full unit (kilometer or mile). The unit of measure (km or miles) for the odometer display is not shown in the VFD. The unit of measure for the instrument cluster odometer/trip odometer is selected at the time that it is manufactured, and cannot be changed. The odometer has a RENTAL CAR mode, which will illuminate the odometer information in the VFD whenever the driver side front door is opened with the ignition switch in the OFF or ACCESSORY positions.
During daylight hours (exterior lamps are OFF) the odometer VFD is illuminated at full brightness for clear visibility. At night (exterior lamps are ON), the VFD lighting level is adjusted with the other cluster general illumination lamps using the panel lamps dimmer function of the interior lighting control sleeve on the left multi-function switch control stalk. However, a PARADE mode position of the control sleeve allows the VFD to be illuminated at full brightness if the exterior lamps are turned ON during daylight hours.
The odometer/trip odometer VFD, the trip odometer switch and the trip odometer push button are serviced as a unit with the instrument cluster.
The instrument cluster gauges, indicators, VFD units, as well as the cluster illumination are all integral components of the CCN and its electronic circuit board. If any part of the internal working components of the instrument cluster become damaged or ineffective, the entire instrument cluster assembly must be replaced. The cluster lens and the cluster hood and mask unit are the only components of the instrument cluster assembly that can be serviced separately.