While in the odometer mode with the ignition switch in the On position and the engine not running, depressing the
odometer/trip odometer switch for about six seconds will display the engine hours information. Holding this switch
depressed while turning the ignition switch from the Off position to the On position will initiate the EMIC self-diag-
nostic 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.
The VFD unit is diagnosed using the EMIC self-diagnostic actuator test. (Refer to 8 - ELECTRICAL/INSTRUMENT
CLUSTER - DIAGNOSIS AND TESTING). Proper testing of the CAN data bus and the electronic data bus message
inputs to the EMIC that control some of the VFD functions requires the use of a diagnostic scan tool. Refer to the
appropriate diagnostic information. Specific operation details for the odometer, the trip odometer, the gear selector
indicator and the various warning and reminder indicator functions of the VFD unit may be found elsewhere in this
service information.
INDICATORS
Indicators are located in various positions within the EMIC and are all connected to the EMIC electronic circuit
board. The door ajar indicator, gate ajar indicator, high beam indicator, and turn signal indicators operate based
upon hard wired inputs to the EMIC. The brake indicator is controlled by CAN data bus messages from the Con-
troller Antilock Brake (CAB) as well as by hard wired park brake switch inputs to the EMIC. The seatbelt indicator
is controlled by the EMIC programming, CAN data bus messages from the Occupant Restraint Controller (ORC),
and a hard wired seat belt switch input to the EMIC. The Malfunction Indicator Lamp (MIL) is normally controlled by
CAN data bus messages from the Powertrain Control Module (PCM); however, if the EMIC loses CAN data bus
communication, the EMIC circuitry will automatically turn the MIL on until CAN data bus communication is restored.
The EMIC uses CAN data bus messages from the Front Control Module (FCM), the PCM, the ORC, the CAB, and
the Sentry Key REmote Entry Module (SKREEM) to control all of the remaining indicators.
The various EMIC indicators are controlled by different strategies; some receive fused ignition switch output from
the EMIC circuitry and have a switched ground, while others are grounded through the EMIC circuitry and have a
switched battery feed. However, all indicators are completely controlled by the EMIC microprocessor based upon
various hard wired and electronic message inputs. The cruise, four low, four lock and tow/haul indicators and those
located within the VFD unit are dimmable. All other indicators are illuminated at a fixed intensity, which is not
affected by the selected illumination intensity of the electro-luminescent EMIC general illumination lamp. The illumi-
nation intensity of the dimmable indicators is synchronized with that of the EMIC general illumination lamp.
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 equip-
ment. The EMIC defaults for the ABS indicator and airbag indicator are enabled, and these configuration settings
must be programmatically disabled in the EMIC using a diagnostic scan tool for vehicles that do not have this equip-
ment. 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 CAN message inputs for that optional system or equipment.
The hard wired indicator inputs may be diagnosed using conventional diagnostic methods. However, the EMIC cir-
cuitry and CAN bus message controlled indicators are diagnosed using the EMIC self-diagnostic actuator test.
(Refer to 8 - ELECTRICAL/INSTRUMENT CLUSTER - DIAGNOSIS AND TESTING). Proper testing of the CAN data
bus and the electronic message inputs to the EMIC that control an indicator requires the use of a diagnostic scan
tool. Refer to the appropriate diagnostic information. Specific details of the operation for each indicator may be
found elsewhere in this service information.
CLUSTER ILLUMINATION
The EMIC has a single electro-luminescent lamp that provides cluster back lighting whenever the exterior lighting is
turned On. The illumination intensity of this lamp is adjusted when the interior lighting thumbwheel on the headlamp
switch is rotated (down to dim, up to brighten) to one of six available minor detent positions. The EMIC monitors a
resistor multiplexed input from the headlamp switch on a dimmer input circuit. In response to that input, the EMIC
electronic circuitry converts a fused 12-volt input it receives on a hard wired panel lamps dimmer switch signal cir-
cuit into a 12-volt Pulse Width Modulated (PWM) output.
The EMIC uses this PWM output to control the illumination intensity of the electro-luminescent cluster illumination
lamp and the VFD unit on the EMIC circuit board, then provides a synchronized PWM output on various hard wired
fused panel lamps dimmer switch signal circuits to control and synchronize the illumination intensity of other incan-
descent illumination lamps in the vehicle. The EMIC also transmits electronic dimming level messages over the CAN
HB
CLUSTER
8J - 41