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 seat belt 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. Proper testing of the
CAN data bus and the electronic message inputs to the EMIC that control an indicator requires the use of a diag-
nostic scan tool. Refer to the appropriate diagnostic information. Specific details of the operation for each indicator
may be found elsewhere in this service information. Each indicator may be individually checked using the scan tool
to check its operation within the EMIC.
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
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.
The hard wired headlamp switch and panel lamps dimmer inputs to and outputs from the EMIC may be diagnosed
using conventional diagnostic methods. However, proper testing of the PWM processing of the EMIC and the elec-
tronic dimming level messages sent by the EMIC over the CAN data bus requires the use of a diagnostic scan tool.
Refer to the appropriate diagnostic information.
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INSTRUMENT CLUSTER - SERVICE INFORMATION
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