Instrument Cluster - Description

DESCRIPTION





The instrument cluster (2) for this vehicle is an ElectroMechanical Instrument Cluster (EMIC) that is located in the instrument panel above the steering column opening, directly in front of the driver. The remainder of the EMIC, including the mounts and the electrical connections, are concealed within the instrument panel below the cluster bezel (1). The instrument cluster for this vehicle also includes the hardware and software necessary to serve as the electronic body control module and is sometimes referred to as the Cab Compartment Node or CCN.

Besides analog gauges and indicators, the EMIC module incorporates one standard and one optional blue-green digital Vacuum Fluorescent Display (VFD) unit. The standard VFD is a fixed segment unit for displaying odometer information, automatic transmission gear selector position (PRNDL), and several other indicators. The optional Compass Mini-Trip Computer (CMTC) VFD unit is a large fixed segment 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 depending upon vehicle equipment.





The EMIC gauges and indicators are visible through a dedicated opening in the instrument panel below the cluster bezel and are protected by a clear plastic cluster lens (5). Nine integral latch formations on the lens secure it to the cluster hood and mask unit (3) as well as the cluster housing (2). Just behind the cluster lens is the cluster hood and integral mask, which is constructed of molded black plastic. The mask is painted silver on vehicles with certain optional trim packages. 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 eight 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 EMIC to the molded plastic instrument panel cluster carrier with two screws.

The rear of the cluster housing and the EMIC electronic circuitry are protected by a molded white plastic rear cover (1), 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 EMIC 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 Light Emitting Diode (LED) 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 CMTC display switch button 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. A black rubber boot (4) seals each switch button to the clearance hole in the lens. 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 EMIC 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 EMIC 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 EMIC 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.

Besides typical instrument cluster gauge and indicator support, the electronic functions and features that the EMIC supports or controls include the following:

- A/C Select and Evaporator Probe Support - The EMIC 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 EMIC 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.
- Compass Mini-Trip Computer Display Support - The EMIC provides support for each of the functions and features of the Compass-Mini-Trip Computer (CMTC) display. This includes support for the compass, thermometer, trip computer and the 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 CMTC display, particularly when multiple display requests are received simultaneously.
- Electric Backlight Support - The EMIC 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 EMIC monitors inputs from the Occupant Restraint Controller (ORC) and 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 EMIC 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 EMIC 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 Totally Integrated Power Module (TIPM) over the CAN data bus to support the 4WD Lock mode functions.
- Horn Switch Support - The EMIC 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 EMIC 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 EMIC 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 EMIC 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 EMIC 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.
- Wiper and Washer Switch Support - The EMIC 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.





The EMIC houses 4 analog gauges and has provisions for up to 25 indicators. Some of the EMIC indicators are automatically configured when the EMIC is connected to the vehicle electrical system for compatibility with certain optional equipment or equipment required for regulatory purposes in certain markets. While each EMIC may have provisions for indicators to support every available option, the configurable indicators will not be functional in a vehicle that does not have the equipment that an indicator supports.

The EMIC includes the following analog gauges:

- Engine Temperature Gauge (23)
- Fuel Gauge (36)
- Speedometer (5)
- Tachometer (16)

The EMIC includes the following VFD units:

- Odometer Display (25) - includes Cruise indicator (17), Gear Selector indicator (15), Malfunction Indicator Lamp (MIL) (27) (domestic market vehicles only), Off Road indicator (26) (Not Used), Push Buttons (24), Tire Pressure Monitor (TPM) indicator (19) and 4WD indicator (18) (domestic market vehicles only).
- Compass Mini-Trip Computer Display (34) - includes Push Button (35).

The EMIC includes provisions for the following indicators:

- Airbag Indicator (14)
- Ajar Indicators - text in odometer display (25) for doors and swing gate
- Antilock Brake System (ABS) Indicator (13)
- Brake Indicator (11) - text only for U.S. market, icon only for markets outside U.S.
- Change Oil Indicator - textual message in odometer display (25) on all domestic market vehicles and only BUX market vehicles equipped with a 2.8L diesel engine and an optional diesel particulate filter
- Charging Indicator (1)
- Cruise Indicator (17)
- Electronic Stability Program (ESP)/Brake Assist System (BAS) Indicator (33)
- Electronic Throttle Control (ETC) Indicator (32)
- Engine Coolant Temperature Indicator (20)
- Four-Wheel Drive (4WD) Indicator (18) - with optional four-wheel drive system only on domestic market vehicles. On export market vehicles, this indicator is located on the right side of the cluster overlay near the top, above the engine coolant temperature gauge.
- Four-Wheel Drive Lock (Off Road) Indicator (26) - Not Used
- Front Axle Lock Indicator (9) - with optional axle lockers only
- Front Fog Lamp Indicator (3) - with optional front fog lamps only
- Front Sway Bar Disconnect Indicator (31) - with optional electronic sway bar disconnect only
- Gas Cap Indicator - textual message in odometer display (25)
- Gear Selector Indicator (15) - with automatic transmission only
- High Beam Indicator (10)
- Low Fuel Indicator (4)
- Low Oil Pressure Indicator (8)
- Malfunction Indicator Lamp (MIL) (27) - only on domestic market vehicles. On export market vehicles, this indicator is located on the right side of the cluster overlay near the top, above the engine coolant temperature gauge.
- No Bus Indicator - textual message in odometer display (25)
- No Fuse Indicator - textual message in odometer display (25)
- Overdrive Off Indicator (28) - with automatic transmission only
- Rear Axle Lock Indicator (12) - with optional axle lockers only
- Rear Fog Lamp Indicator (21) - in markets where rear fog lamps are available only
- Seat Belt Indicator (7)
- Security Indicator (22)
- Tire Pressure Monitor (TPM) Indicator (19)
- Traction Control/Electronic Stability Program (ESP) Indicator (29)
- Turn Signal (Right and Left) Indicators (6)
- Wait-To-Start Indicator (30) - with diesel engine only
- Water-In-Fuel Indicator (2) - with diesel engine only

Each indicator in the EMIC, except those located within a VFD unit, is illuminated by a dedicated LED that is soldered onto the EMIC electronic circuit board. Cluster illumination is accomplished by several dimmable LED units, which illuminate each of the gauge dial faces for visibility when the exterior lighting is turned ON. These LED units are not available for service replacement and, if damaged or ineffective, the entire EMIC must be replaced.

Hard wired circuitry connects the EMIC 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 EMIC 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 EMIC module for this vehicle is serviced only as a complete unit. The EMIC module cannot be adjusted or repaired. If a gauge, an LED unit, a VFD unit, the electronic circuit board, the circuit board hardware, the cluster overlay or the cluster housing are damaged or ineffective, the entire EMIC module must be replaced. The cluster lens and the cluster hood and mask unit are available for separate service replacement.