INSTRUMENT CLUSTER

The instrument cluster (2) for this vehicle is an ElectroMechanical Instrument Cluster (EMIC) that is located in the instrument panel (1) 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 behind the cluster bezel. Besides analog gauges and indicators, the EMIC module incorporates a blue-green digital Vacuum Fluorescent Display (VFD) unit for displaying odometer or trip odometer information, numerous textual warning or reminder indicators and certain diagnostic information.

The EMIC gauges and indicators are visible through a dedicated opening in the cluster bezel on the instrument panel and are protected by a clear plastic cluster lens that is integral to a cluster lens, hood and mask unit (3). Just behind the cluster lens is the cluster hood and an integral cluster mask, which are constructed of molded black plastic. Two cluster masks are used; a base black version is used on base vehicles, while a premium black version features a chrome trim ring around the perimeter of each gauge opening and is used on premium vehicles.

A black plastic odometer/trip odometer switch button protrudes through dedicated holes in the cluster mask and the cluster lens near the lower edge of the cluster just to the right of the tachometer. The molded plastic EMIC lens, hood and mask unit has three integral mounting tabs, one on each of the lower outboard corners of the unit and one on the upper surface of the hood near the center. These mounting tabs are used to secure the EMIC to the molded plastic instrument panel cluster carrier with two screws at the top, and one screw at each outboard tab.

The rear of the cluster housing (2) and the EMIC electronic circuitry are protected by a molded plastic rear cover (1), which is secured to the cluster lens, hood and mask unit with six screws (4). The rear cover includes clearance holes for service access to each of the nine incandescent bulb and bulb holder units installed on the cluster circuit board for general illumination lighting and for the cluster connector receptacle. The single connector receptacle on the back of the cluster electronic circuit board connects the EMIC to the vehicle electrical system through a single dedicated take out and connector of the instrument panel wire harness.

Sandwiched between the rear cover and the lens, hood and mask unit is the cluster housing. The molded plastic cluster housing serves as the carrier for the cluster circuit board and circuitry, the cluster connector receptacle, the gauges, a Light Emitting Diode (LED) for each cluster indicator, the VFD unit, an audible tone transducer, the cluster overlay, the gauge pointers, the odometer/trip odometer switch and the switch button.

Behind the cluster lens, hood, and mask unit on the face of the cluster housing is the cluster overlay. 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 various indicators and the incandescent illumination lamps behind it to be visible through the outer layer of the overlay only through predetermined stencil-like cutouts. A rectangular opening in the overlay at the base of the tachometer dial face has a smoked clear lens through which the illuminated VFD unit can be viewed.

The EMIC houses four analog gauges, one odometer/trip odometer VFD unit 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 (21)
• Fuel Gauge (31)
• Speedometer (9)
• Tachometer (12)

The EMIC includes the following VFD display unit and control:

• Odometer Display (23) - Includes ajar indicators (without Electronic Vehicle Information Center (EVIC) only), cruise indicator, gas cap indicator (with gasoline engines only), low coolant indicator (with diesel engine only), odometer, trip odometer.
• Odometer/Trip Odometer Switch Button (22)

The EMIC includes provisions for the following indicators:

• Airbag Indicator (3)
• Ajar Indicators - textual messages in odometer VFD (23) for doors, tailgate and rear flip-up glass.
• Antilock Brake System (ABS) Indicator (18)
• Brake Indicator (28)
• Charging Indicator (19)
• Coolant Low Indicator - textual message in odometer VFD (23) with diesel engine only.
• Cruise Indicator - text in odometer VFD (23).
• Electronic Stability Program (ESP)/Brake Assist System (BAS) Indicator (7)
• Electronic Throttle Control (ETC) Indicator (1) - with diesel engine only.
• Four-Wheel Drive Full Time Indicator (29) - with Selec-Trac transfer case only.
• Four-Wheel Drive Low Mode Indicator (14) - with four-wheel drive only.
• Four-Wheel Drive Part Time Indicator (27) - with four-wheel drive only.
• Front Fog Lamp Indicator (15) - with front fog lamps only.
• Gas Cap Indicator - with gasoline engine only in odometer VFD (23).
• High Beam Indicator (11)
• Light Bar Lamp Indicator (8) - with light bar lamps only.
• Low Fuel Indicator (2)
• Low Oil Pressure Indicator (24)
• Malfunction Indicator Lamp (MIL) (16)
• Overdrive Off Indicator (4) - with automatic transmission only.
• Rear Fog Lamp Indicator (17) - with rear fog lamps only.
• Seat Belt Indicator (6)
• Security Indicator (30)
• Tire Pressure Monitor (TPM) Indicator (13)
• Traction Control/Electronic Stability Program (ESP) Indicator (25)
• Transmission Overtemp Indicator (26) - with automatic transmission only.
• Turn Signal (Right and Left) Indicators (10)
• Wait-To-Start Indicator (5) - with diesel engine only.
• Water-In-Fuel Indicator (20) - with diesel engine only.

Each indicator in the EMIC, except the cruise indicator located within the odometer/trip odometer VFD unit, is illuminated by a dedicated Light Emitting Diode (LED) that is soldered onto the EMIC electronic circuit board. Cluster illumination is accomplished by dimmable incandescent back lighting, which illuminates the gauges for visibility when the exterior lighting is turned ON. The LED units are not available for service replacement and, if damaged or ineffective, the entire EMIC must be replaced. Each of the incandescent bulbs is secured by an integral bulb holder to the electronic circuit board from the back of the cluster housing.

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, the VFD unit, the electronic circuit board, the circuit board hardware, the cluster overlay, or the EMIC housing are damaged or ineffective, the entire EMIC module must be replaced. The cluster lens, hood and mask unit and the incandescent general illumination lamp bulbs with holders are available for individual service replacement.

OPERATION

The ElectroMechanical Instrument Cluster (EMIC) 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 EMIC 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 EMIC is installed in the instrument panel so that all of these monitors can be easily viewed by the vehicle operator when driving, while still allowing relative ease of access for service.

GAUGES

All gauges receive battery current through the EMIC circuitry when the ignition switch is in the ON or START positions. With the ignition switch in the OFF position battery current is not supplied to any gauges, and the EMIC circuitry is programmed to move all of the gauge needles back to the low end of their respective scales. Therefore, the gauges do not accurately indicate any vehicle condition unless the ignition switch is in the ON or START positions.

All of the EMIC gauges are air core magnetic units. Two fixed electromagnetic coils are located within each gauge. These coils are wrapped at right angles to each other around a movable permanent magnet. The movable magnet is suspended within the coils on one end of a pivot shaft, while the gauge needle is attached to the other end of the shaft. One of the coils has a fixed current flowing through it to maintain a constant magnetic field strength. Current flow through the second coil changes, which causes changes in its magnetic field strength. The current flowing through the second coil is changed by the EMIC circuitry in response to messages received over the PCI data bus. The gauge needle moves as the movable permanent magnet aligns itself to the changing magnetic fields created around it by the electromagnets.

VACUUM-FLUORESCENT DISPLAY

The Vacuum-Fluorescent Display (VFD) unit is soldered to the EMIC electronic circuit board. With the ignition switch in the OFF or ACCESSORY positions, the odometer display is activated when the driver door is opened (Rental Car mode) and is deactivated when the driver door is closed. Otherwise, the display unit is active when the ignition switch is in the ON or START positions, and inactive when the ignition switch is in the OFF or ACCESSORY positions.

The illumination intensity of the VFD unit is controlled by the EMIC circuitry based upon electronic dimming level messages received from the BCM over the PCI data bus, and is synchronized with the illumination intensity of other VFD units in the vehicle. The BCM provides dimming level messages based upon internal programming and inputs it receives from the circuitry of the multi-function switch on the steering column based upon the settings of the control knob and control ring on the left (lighting) control stalk that have been selected by the vehicle operator.

The EMIC VFD unit has several display capabilities including odometer, trip odometer, some warning or reminder indications, and various diagnostic information when certain fault conditions exist. On vehicles equipped with the optional Electronic Vehicle Information Center (EVIC), most of the odometer VFD unit warning and reminder indications are suppressed so as not to duplicate indications that are provided by the EVIC. The odometer VFD warning and reminder messages include:

• door - indicating a door is ajar (on vehicles without the optional EVIC only).
• gascap - indicating that the fuel tank filler cap is loose or that there is a gross leak in the fuel vapor recovery system (on vehicles with a gasoline engine only).
• gate - indicating the tailgate is ajar (on vehicles without the optional EVIC only).
• glass - indicating the tailgate glass is ajar (on vehicles without the optional EVIC only).
• locool - indicating the engine coolant level is low (on vehicles with an optional diesel engine only).
• no bus - indicating there is no PCI data bus communication detected.

An odometer/trip odometer switch on the EMIC circuit board is used to control some of the display modes. This switch is actuated manually by depressing the odometer/trip odometer switch button that extends through the lower edge of the cluster lens, just right of the tachometer. Actuating this switch momentarily with the ignition switch in the ON position will toggle the VFD between the odometer and trip odometer modes. Depressing the switch button for about two seconds while the VFD is in the trip odometer mode will reset the trip odometer value to zero. The VFD can be reverted to the odometer display and any currently displayed textual messages suspended by momentarily depressing and releasing the odometer/trip odometer switch button.

Holding this switch button depressed while turning the ignition switch from the OFF position to the ON position will initiate the EMIC self-diagnostic actuator test. The VFD will also display the cluster software version level near the completion of the EMIC self-diagnostic actuator test. Refer to the instrument cluster diagnosis and testing service information for additional details on this cluster function. The EMIC microprocessor remembers which display mode is active when the ignition switch is turned to the OFF position, and returns the VFD display to that mode when the ignition switch is turned ON again.

INDICATORS

Indicators are located in various positions within the EMIC and are all connected to the EMIC electronic circuit board. Some indicators operate based upon hard wired inputs to the EMIC, but most are controlled by PCI data bus messages from other electronic modules in the vehicle. Some are controlled by a combination of hard wired inputs, electronic messaging and EMIC programming. If the EMIC loses PCI data bus communication, the EMIC circuitry will automatically turn ON the Malfunction Indicator Lamp (MIL) until PCI data bus communication is restored.

The various EMIC indicators are controlled by different strategies; some receive fused ignition switch output from the EMIC circuitry and have a switched ground, others are grounded through the EMIC circuitry and have a switched battery feed, while still others are completely controlled by the EMIC microprocessor based upon various hard wired and electronic message inputs. Some indicators are illuminated at a fixed intensity, while the illumination intensity of others is synchronized with that of the EMIC general illumination lighting.

In addition, certain indicators in this instrument cluster are automatically configured or self-configured. This feature allows the configurable indicators to be enabled by the EMIC circuitry for compatibility with certain optional equipment. The ABS indicator, airbag indicator, and Tire Pressure Monitor (TPM) indicator are automatically configured by PCI data bus messages received by the EMIC from the CAB, ACM or EVIC after the EMIC is installed in the vehicle. Once these configuration settings are learned by the EMIC, a diagnostic scan tool must be used to remove these settings from the non-volatile memory of the EMIC. The automatically configured or self-configured indicators remain latent in each EMIC at all times and will be active only when the EMIC receives the appropriate PCI message inputs for the optional system or equipment.

CLUSTER ILLUMINATION

The EMIC has several incandescent illumination lamps that provide cluster back lighting whenever the exterior lighting is turned ON. The illumination intensity of these lamps is adjusted when the interior lighting control ring on the left control stalk of the multi-function switch is rotated (down to dim, up to brighten) to one of six available minor detent positions. The Body Control Module (BCM) monitors a resistor multiplexed input from the multi-function switch on a panel lamps dimmer switch mux circuit. In response to that input, the BCM provides a control output to energize the park lamp relay and transmits an electronic dimming level message to the EMIC over the PCI data bus based upon internal programming.

The EMIC receives the electronic dimming level message from the BCM, and a battery current input from the energized park lamp relay on the hard wired fused park lamp relay output circuit. Based upon the dimming level message, the EMIC then converts the battery current input to the appropriate 12-volt Pulse Width Modulated (PWM) output. This PWM output is used to illuminate the cluster illumination lamps and the VFD unit on the EMIC circuit board, and provides a PWM output on the hard wired fused panel lamps dimmer switch signal circuit to control and synchronize the illumination intensity of other incandescent illumination lamps in the vehicle. The cluster illumination lamps are grounded at all times.

The BCM also transmits electronic dimming level messages over the PCI data bus to other electronic modules in the vehicle to control and synchronize the illumination intensity of their VFD units to that of the EMIC VFD unit. In addition, the control ring on the left (lighting) control stalk of the multi-function switch has a PARADE mode position to provide a PARADE (or funeral) mode. The BCM monitors the request for this mode from the multi-function switch, then transmits an electronic dimming level message to illuminate all VFD units in the vehicle at full (daytime) intensity for easier visibility when driving in daylight with the exterior lighting turned ON.

The hard wired multi-function switch and panel lamps dimmer inputs to and outputs from the EMIC may be diagnosed using conventional diagnostic tools and procedures. However, proper testing of the PWM output of the EMIC and the electronic dimming level messages sent by the BCM over the PCI data bus requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.

INPUT AND OUTPUT CIRCUITS

HARD WIRED INPUTS

The hard wired inputs to the EMIC include the following:

• BCM Wake Up Input
• Driver Side Front Seat Belt Switch Sense
• Fused B(+) - Ignition-Off Draw
• Fused Ignition Switch Output (Run-Start)
• Fused Park Lamp Relay Output
• Left Turn Signal
• Low Coolant Fluid Level Sense - with Diesel Engine
• Park Brake Switch Sense
• Passenger Side Front Seat Belt Switch Sense
• Red Brake Warning Indicator Driver
• Right Turn Signal
• VTSS Indicator Driver

Refer to the appropriate wiring information for additional details.

HARD WIRED OUTPUTS

The hard wired outputs of the EMIC include the following:

• Fused Panel Lamps Dimmer Switch Signal

Refer to the appropriate wiring information for additional details.

GROUNDS

The EMIC receives a ground path through the following hard wired circuits:

• Power Ground

Refer to the appropriate wiring information for additional details.

COMMUNICATION

The EMIC has provisions for the following communication circuits:

• PCI Data Bus

Refer to the appropriate wiring information for additional details.

REMOVAL

WARNING: To avoid personal injury or death, on vehicles equipped with airbags, disable the supplemental restraint system before attempting any steering wheel, steering column, airbag, occupant classification system, seat belt tensioner, impact sensor, or instrument panel component diagnosis or service. Disconnect and isolate the battery negative (ground) cable, then wait two minutes for the system capacitor to discharge before performing further diagnosis or service. This is the only sure way to disable the supplemental restraint system. Failure to take the proper precautions could result in accidental airbag deployment.

CLUSTER BULB

NOTE: This procedure applies to each of the incandescent cluster illumination lamp and bulb holder units.

CLUSTER LENS, HOOD, AND MASK

CLUSTER BULB

CAUTION: Always use the correct bulb size and type for replacement. An incorrect bulb size or type may overheat and cause damage to the instrument cluster, the electronic circuit board or the gauges.

NOTE: This procedure applies to each of the incandescent cluster illumination lamp and bulb holder units.

CLUSTER LENS, HOOD, AND MASK