2003 DODGE RAM Diesel

The EMIC microprocessor smooths the input data
using algorithms to provide gauge readings that are
accurate, stable and responsive to operating condi-
tions. These algorithms are designed to provide
gauge readings during normal operation that are con-
sistent with customer expectations. However, when
abnormal conditions exist such as high coolant tem-
perature, the algorithm can drive the gauge pointer
to an extreme position and the microprocessor can
sound a chime through the on-board audible tone
generator to provide distinct visual and audible indi-
cations of a problem to the vehicle operator. The
instrument cluster circuitry may also produce audi-
ble warnings for other electronic modules in the vehi-
cle based upon electronic tone request messages
received over the PCI data bus. Each audible warn-
ing is intended to provide the vehicle operator with
an audible alert to supplement a visual indication.The EMIC circuitry operates on battery current
received through a fused B(+) fuse in the Integrated
Power Module (IPM) on a non-switched fused B(+)
circuit, and on battery current received through a
fused ignition switch output (run-start) fuse in the
IPM on a fused ignition switch output (run-start) cir-
cuit. This arrangement allows the EMIC to provide
some features regardless of the ignition switch posi-
tion, while other features will operate only with the
ignition switch in the On or Start positions. The
EMIC circuitry is grounded through a ground circuit
and take out of the instrument panel wire harness
with an eyelet terminal connector that is secured by
a ground screw to a ground location near the center
of the instrument panel structural support.
The EMIC also has a self-diagnostic actuator test
capability, which will test each of the PCI bus mes-
sage-controlled functions of the cluster by lighting
the appropriate indicators, positioning the gauge nee-
Fig. 4 Gauges & Indicators - Diesel Engine
1 - MALFUNCTION INDICATOR LAMP 14 - ENGINE TEMPERATURE GAUGE
2 - VOLTAGE GAUGE 15 - SECURITY INDICATOR
3 - LEFT TURN INDICATOR 16 - GEAR SELECTOR INDICATOR DISPLAY (INCLUDES
CRUISE & UPSHIFT INDICATORS)
4 - TACHOMETER 17 - WATER-IN-FUEL INDICATOR
5 - AIRBAG INDICATOR 18 - BRAKE INDICATOR
6 - HIGH BEAM INDICATOR 19 - WAIT-TO-START INDICATOR
7 - SEATBELT INDICATOR 20 - ODOMETER/TRIP ODOMETER DISPLAY (INCLUDES
ENGINE HOURS, WASHER FLUID, LAMP OUTAGE,
OVERDRIVE-OFF & SERVICE 4x4 INDICATORS)
8 - SPEEDOMETER 21 - ODOMETER/TRIP ODOMETER SWITCH BUTTON
9 - RIGHT TURN INDICATOR 22 - FUEL GAUGE
10 - OIL PRESSURE GAUGE 23 - LOW FUEL INDICATOR
11 - CARGO LAMP INDICATOR 24 - TRANSMISSION OVERTEMP INDICATOR
12 - DOOR AJAR INDICATOR 25 - CHECK GAUGES INDICATOR
13 - ABS INDICATOR
DRINSTRUMENT CLUSTER 8J - 7
INSTRUMENT CLUSTER (Continued)

ajar indicator, high beam indicator, and turn signal
indicators operate based upon hard wired inputs to
the EMIC. The brake indicator is controlled by PCI
data bus messages from the Controller 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, PCI data bus
messages from the Airbag Control Module (ACM),
and a hard wired seat belt switch input to the EMIC.
The Malfunction Indicator Lamp (MIL) is normally
controlled by PCI data bus messages from the Pow-
ertrain Control Module (PCM); however, if the EMIC
loses PCI data bus communication, the EMIC cir-
cuitry will automatically turn the MIL on until PCI
data bus communication is restored. The EMIC uses
PCI data bus messages from the Front Control Mod-
ule (FCM), the PCM, the diesel engine only Engine
Control Module (ECM), the ACM, the CAB, and the
Sentry Key Immobilizer Module (SKIM) to control all
of the remaining indicators.
The various EMIC indicators are controlled by dif-
ferent 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. All indicators are illumi-
nated at a fixed intensity, which is not affected by
the selected illumination intensity of the EMIC gen-
eral illumination lamps.
In addition, certain indicators in this instrument
cluster are automatically configured or self-config-
ured. This feature allows the configurable indicators
to be enabled by the EMIC circuitry for compatibility
with certain optional equipment. 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
DRBIIItscan tool for vehicles that do not have this
equipment. The automatically configured or self-con-
figured indicators remain latent in each EMIC at all
times and will be active only when the EMIC
receives the appropriate PCI message inputs for that
optional system or equipment.
The hard wired indicator inputs may be diagnosed
using conventional diagnostic methods. However, the
EMIC circuitry and PCI bus message controlled indi-
cators are diagnosed using the EMIC self-diagnostic
actuator test. (Refer to 8 - ELECTRICAL/INSTRU-
MENT CLUSTER - DIAGNOSIS AND TESTING).
Proper testing of the PCI data bus and the electronic
message inputs to the EMIC that control an indicator
requires the use of a DRBIIItscan tool. Refer to the
appropriate diagnostic information. Specific details ofthe operation for each indicator may be found else-
where in this service information.
CLUSTER ILLUMINATION
The EMIC has several illumination lamps that are
illuminated when the exterior lighting is turned on
with the headlamp switch. The illumination intensity
of these lamps 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 mul-
tiplexed input from the headlamp switch on a dim-
mer input circuit. In response to that input, the
EMIC electronic circuitry converts a 12-volt input it
receives from a fuse in the Integrated Power Module
(IPM) on a hard wired panel lamps dimmer switch
signal circuit into a 12-volt Pulse Width Modulated
(PWM) output. The EMIC uses this PWM output to
power the cluster illumination lamps and the VFD
units on the EMIC circuit board, then provides a syn-
chronized PWM output on the various hard wired
fused panel lamps dimmer switch signal circuits 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 EMIC also sends 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 units. In addition, the thumbwheel
on the headlamp switch has a Parade Mode position
to provide a parade mode. The EMIC monitors the
request for this mode from the headlamp switch,
then sends an electronic dimming level message over
the PCI data bus 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 headlamp switch and EMIC panel
lamps dimmer inputs and outputs may be diagnosed
using conventional diagnostic methods. However,
proper testing of the PWM output of the EMIC and
the electronic dimming level messages sent by the
EMIC over the PCI data bus requires the use of a
DRBIIItscan tool. Refer to the appropriate diagnos-
tic information.
INPUT AND OUTPUT CIRCUITS
HARD WIRED INPUTS
The hard wired inputs to the EMIC include the fol-
lowing:
²Brake Lamp Switch Output
²Driver Cylinder Lock Switch Sense
²Driver Door Ajar Switch Sense
DRINSTRUMENT CLUSTER 8J - 9
INSTRUMENT CLUSTER (Continued)

NOTE: Certain indicators in this instrument cluster
are automatically configured. This feature allows
those indicators to be activated or deactivated for
compatibility with certain optional equipment. If the
problem being diagnosed involves improper illumi-
nation of the cruise indicator, the electronic throttle
control indicator, the overdrive-off indicator, the
service four-wheel drive indicator, the transmission
overtemp indicator, the upshift indicator, the secu-
rity indicator or the gear selector indicator, discon-
nect and isolate the battery negative cable. After
about five minutes, reconnect the battery negative
cable and turn the ignition switch to the On posi-
tion. The instrument cluster should automatically
relearn the equipment in the vehicle and properly
configure the configurable indicators accordingly.
ABS INDICATOR
DESCRIPTION
An Antilock Brake System (ABS) indicator is stan-
dard equipment on all instrument clusters. However,
the instrument cluster can be programmed to disable
this indicator on vehicles that are not equipped with
the ABS or Rear Wheel Anti-Lock (RWAL) brake sys-
tems, which are not available in some markets. On
vehicles equipped with a gasoline engine, the ABS
indicator is located near the lower edge of the instru-
ment cluster, between the tachometer and the speed-
ometer. On vehicles equipped with a diesel engine,
the ABS indicator is located on the right side of the
instrument cluster, to the right of the engine temper-
ature gauge. The ABS indicator consists of a stencil-
like cutout of the International Control and Display
Symbol icon for ªFailure of Anti-lock Braking Sys-
temº in the opaque layer of the instrument cluster
overlay. The dark outer layer of the overlay prevents
the indicator from being clearly visible when it is not
illuminated. An amber Light Emitting Diode (LED)
behind the cutout in the opaque layer of the overlay
causes the icon to appear in amber through the
translucent outer layer of the overlay when the indi-
cator is illuminated from behind by the LED, which
is soldered onto the instrument cluster electronic cir-
cuit board. The ABS indicator is serviced as a unit
with the instrument cluster.
OPERATION
The ABS indicator gives an indication to the vehi-
cle operator when the ABS system is faulty or inop-
erative. This indicator is controlled by a transistor on
the instrument cluster circuit board based upon clus-
ter programming and electronic messages received by
the cluster from the Controller Antilock Brake (CAB)over the Programmable Communications Interface
(PCI) data bus. The ABS indicator Light Emitting
Diode (LED) is completely controlled by the instru-
ment cluster logic circuit, and that logic will only
allow this indicator to operate when the instrument
cluster receives a battery current input on the fused
ignition switch output (run-start) circuit. Therefore,
the LED will always be off when the ignition switch
is in any position except On or Start. The LED only
illuminates when it is provided a path to ground by
the instrument cluster transistor. The instrument
cluster will turn on the ABS indicator for the follow-
ing reasons:
²Bulb Test- Each time the ignition switch is
turned to the On position the ABS indicator is illu-
minated by the cluster for about two seconds as a
bulb test.
²ABS Lamp-On Message- Each time the clus-
ter receives a lamp-on message from the CAB, the
ABS indicator will be illuminated. The indicator
remains illuminated until the cluster receives a
lamp-off message from the CAB, or until the ignition
switch is turned to the Off position, whichever occurs
first.
²Communication Error- If the cluster receives
no lamp-on or lamp-off messages from the CAB for
three consecutive seconds, the ABS indicator is illu-
minated. The indicator remains illuminated until the
cluster receives a valid message from the CAB, or
until the ignition switch is turned to the Off position,
whichever occurs first.
²Actuator Test- Each time the instrument clus-
ter is put through the actuator test, the ABS indica-
tor will be turned on, then off again during the bulb
check portion of the test to confirm the functionality
of the LED and the cluster control circuitry.
²ABS Diagnostic Test- The ABS indicator is
blinked on and off by lamp-on and lamp-off messages
from the CAB during the performance of the ABS
diagnostic tests.
The CAB continually monitors the ABS circuits
and sensors to decide whether the system is in good
operating condition. The CAB then sends the proper
lamp-on or lamp-off messages to the instrument clus-
ter. If the CAB sends a lamp-on message after the
bulb test, it indicates that the CAB has detected a
system malfunction and/or that the ABS system has
become inoperative. The CAB will store a Diagnostic
Trouble Code (DTC) for any malfunction it detects.
Each time the ABS indicator fails to light due to an
open or short in the cluster ABS indicator circuit, the
cluster sends a message notifying the CAB of the
condition, then the instrument cluster and the CAB
will each store a DTC. For proper diagnosis of the
antilock brake system, the CAB, the PCI data bus, or
the electronic message inputs to the instrument clus-
DRINSTRUMENT CLUSTER 8J - 17
INSTRUMENT CLUSTER (Continued)

input from the headlamp switch, or until the ignition
switch is turned to the Off position, whichever occurs
first.
²Actuator Test- Each time the cluster is put
through the actuator test, the cargo lamp indicator
will be turned on, then off again during the bulb
check portion of the test to confirm the functionality
of the LED and the cluster control circuitry.
The instrument cluster continually monitors the
headlamp dimmer switch circuit to determine the
proper interior lamps features and panel lamps illu-
mination levels to provide. The cluster then energizes
and de-energizes a low side driver circuit to control
the exterior cargo lamp. Each time the instrument
cluster energizes the cargo lamp driver and the igni-
tion switch is in the On or start positions, the cluster
also turns on the cargo lamp indicator. For further
diagnosis of the cargo lamp indicator or the instru-
ment cluster circuitry that controls the indicator,
(Refer to 8 - ELECTRICAL/INSTRUMENT CLUS-
TER - DIAGNOSIS AND TESTING). For proper
diagnosis of the cargo lamp or the headlamp switch
inputs to the instrument cluster that control the
cargo lamp indicator, a DRBIIItscan tool is required.
Refer to the appropriate diagnostic information.
CHECK GAUGES INDICATOR
DESCRIPTION
A check gauges indicator is standard equipment on
all instrument clusters. On vehicles equipped with a
gasoline engine, the check gauges indicator is located
near the lower edge of the instrument cluster,
between the tachometer and the speedometer. On
vehicles equipped with a diesel engine, the check
gauges indicator is located on the left side of the
instrument cluster, to the left of the voltage gauge.
The check gauges indicator consists of a stencil-like
cutout of the words ªCHECK GAGESº in the opaque
layer of the instrument cluster overlay. The dark
outer layer of the overlay prevents the indicator from
being clearly visible when it is not illuminated. A red
Light Emitting Diode (LED) behind the cutout in the
opaque layer of the overlay causes the ªCHECK
GAGESº text to appear in red through the translu-
cent outer layer of the overlay when the indicator is
illuminated from behind by the LED, which is sol-
dered onto the instrument cluster electronic circuit
board. The check gauges indicator is serviced as a
unit with the instrument cluster.
OPERATION
The check gauges indicator gives an indication to
the vehicle operator when certain instrument cluster
gauge readings reflect a condition requiring immedi-ate attention. This indicator is controlled by a tran-
sistor on the instrument cluster circuit board based
upon cluster programming and electronic messages
received by the cluster from the Powertrain Control
Module (PCM) on vehicles equipped with a gasoline
engine, or from the Engine Control Module (ECM) on
vehicles equipped with a diesel engine over the Pro-
grammable Communications Interface (PCI) data
bus. The check gauges indicator Light Emitting
Diode (LED) is completely controlled by the instru-
ment cluster logic circuit, and that logic will only
allow this indicator to operate when the instrument
cluster receives a battery current input on the fused
ignition switch output (run-start) circuit. Therefore,
the LED will always be off when the ignition switch
is in any position except On or Start. The LED only
illuminates when it is provided a path to ground by
the instrument cluster transistor. The instrument
cluster will turn on the check gauges indicator for
the following reasons:
²Bulb Test- Each time the ignition switch is
turned to the On position the check gauges indicator
is illuminated for about two seconds as a bulb test.
²Engine Temperature High Message- Each
time the cluster receives a message from the PCM or
ECM indicating the engine coolant temperature of a
gasoline engine is about 122É C (252É F) or higher, or
of a diesel engine is about 112É C (233É F) or higher,
the check gauges indicator will be illuminated. The
indicator remains illuminated until the cluster
receives a message from the PCM or ECM indicating
that the engine coolant temperature of a gasoline
engine is below about 122É C (252É F), or of a diesel
engine is below about 112É C (233É F), or until the
ignition switch is turned to the Off position, which-
ever occurs first.
²Engine Oil Pressure Low Message- Each
time the cluster receives a message from the PCM or
ECM indicating the engine oil pressure is about 41
kPa (6 psi) or lower, the check gauges indicator will
be illuminated. The indicator remains illuminated
until the cluster receives a message from the PCM or
ECM indicating that the engine oil pressure is above
about 41 kPa (6 psi), or until the ignition switch is
turned to the Off position, whichever occurs first.
The cluster will only turn the indicator on in
response to an engine oil pressure low message if the
engine speed is greater than zero.
²System Voltage Low (Charge Fail) Message
- Each time the cluster receives a message from the
PCM or ECM indicating the electrical system voltage
is less than about 11.5 volts (charge fail condition),
the check gauges indicator will be illuminated. The
indicator remains illuminated until the cluster
receives a message from the PCM or ECM indicating
the electrical system voltage is greater than about
DRINSTRUMENT CLUSTER 8J - 21
CARGO LAMP INDICATOR (Continued)

12.0 volts (but less than 16.0 volts), or until the igni-
tion switch is turned to the Off position, whichever
occurs first.
²System Voltage High Message- Each time
the cluster receives a message from the PCM or ECM
indicating the electrical system voltage is greater
than about 16.0 volts, the check gauges indicator will
be illuminated. The indicator remains illuminated
until the cluster receives a message from the PCM or
ECM indicating the electrical system voltage is less
than about 15.5 volts (but greater than 11.5 volts), or
until the ignition switch is turned to the Off position,
whichever occurs first.
²Actuator Test- Each time the cluster is put
through the actuator test, the check gauges indicator
will be turned on, then off again during the bulb
check portion of the test to confirm the functionality
of the LED and the cluster control circuitry.
On vehicles with a gasoline engine, the PCM con-
tinually monitors the engine temperature, oil pres-
sure, and electrical system voltage, then sends the
proper messages to the instrument cluster. On vehi-
cles with a diesel engine, the ECM continually mon-
itors the engine temperature, oil pressure, and
electrical system voltage, then sends the proper mes-
sages to the instrument cluster. For further diagnosis
of the check gauges indicator or the instrument clus-
ter circuitry that controls the LED, (Refer to 8 -
ELECTRICAL/INSTRUMENT CLUSTER - DIAGNO-
SIS AND TESTING). For proper diagnosis of the
PCM, the ECM, the PCI data bus, or the electronic
message inputs to the instrument cluster that control
the check gauges indicator, a DRBIIItscan tool is
required. Refer to the appropriate diagnostic infor-
mation.
CRUISE INDICATOR
DESCRIPTION
A cruise indicator is standard equipment on all
instrument clusters. However, on vehicles not
equipped with the optional speed control system, this
indicator is electronically disabled. The cruise indica-
tor consists of the word ªCRUISEº, which appears in
the lower portion of the gear selector indicator Vacu-
um-Fluorescent Display (VFD) unit. The VFD is sol-
dered onto the cluster electronic circuit board and is
visible through a window with a smoked clear lens
located on the lower edge of the speedometer gauge
dial face of the cluster overlay. The dark lens over
the VFD prevents the indicator from being clearly
visible when it is not illuminated. The word
ªCRUISEº appears in a blue-green color and at the
same lighting level as the gear selector indicator
information when it is illuminated by the instrumentcluster electronic circuit board. The cruise indicator
is serviced as a unit with the VFD in the instrument
cluster.
OPERATION
The cruise indicator gives an indication to the vehi-
cle operator when the speed control system is turned
On, regardless of whether the speed control is
engaged. This indicator is controlled by the instru-
ment cluster circuit board based upon cluster pro-
gramming and electronic messages received by the
cluster from the Powertrain Control Module (PCM)
over the Programmable Communications Interface
(PCI) data bus. The cruise indicator is completely
controlled by the instrument cluster logic circuit, and
that logic will only allow this indicator to operate
when the instrument cluster receives a battery cur-
rent input on the fused ignition switch output (run-
start) circuit. Therefore, the indicator will always be
off when the ignition switch is in any position except
On or Start. The indicator only illuminates when it is
switched to ground by the instrument cluster cir-
cuitry. The instrument cluster will turn on the cruise
indicator for the following reasons:
²Cruise Lamp-On Message- Each time the
cluster receives a cruise lamp-on message from the
PCM indicating the speed control system has been
turned On, the cruise indicator is illuminated. The
indicator remains illuminated until the cluster
receives a cruise lamp-off message from the PCM or
until the ignition switch is turned to the Off position,
whichever occurs first.
²Actuator Test- Each time the cluster is put
through the actuator test, the cruise indicator will be
turned on, then off again during the VFD portion of
the test to confirm the functionality of the VFD and
the cluster control circuitry.
The PCM continually monitors the speed control
switches to determine the proper outputs to the
speed control servo. The PCM then sends the proper
cruise indicator lamp-on and lamp-off messages to
the instrument cluster. For further diagnosis of the
cruise indicator or the instrument cluster circuitry
that controls the indicator, (Refer to 8 - ELECTRI-
CAL/INSTRUMENT CLUSTER - DIAGNOSIS AND
TESTING). For proper diagnosis of the speed control
system, the PCM, the PCI data bus, or the electronic
message inputs to the instrument cluster that control
the cruise indicator, a DRBIIItscan tool is required.
Refer to the appropriate diagnostic information.
8J - 22 INSTRUMENT CLUSTERDR
CHECK GAUGES INDICATOR (Continued)

DOOR AJAR INDICATOR
DESCRIPTION
A door ajar indicator is standard equipment on all
instrument clusters. The door ajar indicator is
located on the right side of the instrument cluster, to
the right of the engine temperature gauge. The door
ajar indicator consists of a stencil-like cutout of the
words ªDOOR AJARº in the opaque layer of the
instrument cluster overlay. The dark outer layer of
the overlay prevents the indicator from being clearly
visible when it is not illuminated. A red Light Emit-
ting Diode (LED) behind the cutout in the opaque
layer of the overlay causes the ªDOOR AJARº text to
appear in red through the translucent outer layer of
the overlay when the indicator is illuminated from
behind by the LED, which is soldered onto the
instrument cluster electronic circuit board. The door
ajar indicator is serviced as a unit with the instru-
ment cluster.
OPERATION
The door ajar indicator gives an indication to the
vehicle operator that one or more of the passenger
compartment doors may be open or not completely
latched. This indicator is controlled by a transistor
on the instrument cluster circuit board based upon
cluster programming and hard wired inputs received
by the cluster from the door ajar switches located in
each door latch unit. The door ajar indicator Light
Emitting Diode (LED) is completely controlled by the
instrument cluster logic circuit, and that logic will
allow this indicator to operate whenever the instru-
ment cluster receives a battery current input on the
fused ignition switch output (run-start) circuit.
Therefore, the LED will always be off when the igni-
tion switch is in any position except On or Start. The
LED only illuminates when it is provided a path to
ground by the instrument cluster transistor. The
instrument cluster will turn on the door ajar indica-
tor for the following reasons:
²Bulb Test- Each time the ignition switch is
turned to the On position the door ajar indicator is
illuminated for about two seconds as a bulb test.
²Door Ajar Switch Input- Each time the clus-
ter detects ground on any one of the door ajar switch
sense circuits (door ajar switch closed = door is open
or not completely latched) the door ajar indicator will
be illuminated. The indicator remains illuminated
until all of the door ajar switch sense inputs to the
cluster are an open circuit (door ajar switch open =
door fully closed), or until the ignition switch is
turned to the Off position, whichever occurs first.
²Actuator Test- Each time the cluster is put
through the actuator test, the door ajar indicator will
be turned on, then off again during the bulb checkportion of the test to confirm the functionality of the
LED and the cluster control circuitry.
The instrument cluster continually monitors the
door ajar switches to determine the status of the
doors. For further diagnosis of the door ajar indicator
or the instrument cluster circuitry that controls the
indicator, (Refer to 8 - ELECTRICAL/INSTRUMENT
CLUSTER - DIAGNOSIS AND TESTING). For
proper diagnosis of the door ajar switches and cir-
cuits, (Refer to 8 - ELECTRICAL/LAMPS/LIGHTING
- INTERIOR/DOOR AJAR SWITCH - DIAGNOSIS
AND TESTING).
ENGINE TEMPERATURE
GAUGE
DESCRIPTION
An engine coolant temperature gauge is standard
equipment on all instrument clusters. The engine
coolant temperature gauge is located in the lower
right quadrant of the instrument cluster, below the
oil pressure gauge. The engine coolant temperature
gauge consists of a movable gauge needle or pointer
controlled by the instrument cluster circuitry and a
fixed 90 degree scale on the cluster overlay that
reads left-to-right from ªCº (or Cold) to ªHº (or Hot)
for gasoline engines. On vehicles with a diesel
engine, the scale reads from ª60ºÉ C to ª120ºÉ C in
markets where a metric instrument cluster is speci-
fied, or from ª140ºÉ F to ª245ºÉ F in all other mar-
kets. An International Control and Display Symbol
icon for ªEngine Coolant Temperatureº is located on
the cluster overlay, directly below the left end of the
gauge scale. The engine coolant temperature gauge
graphics are black against a white field except for
two red graduations at the high end of the gauge
scale, making them clearly visible within the instru-
ment cluster in daylight. When illuminated from
behind by the panel lamps dimmer controlled cluster
illumination lighting with the exterior lamps turned
On, the black graphics appear blue and the red
graphics still appear red. The orange gauge needle is
internally illuminated. Gauge illumination is pro-
vided by replaceable incandescent bulb and bulb
holder units located on the instrument cluster elec-
tronic circuit board. The engine coolant temperature
gauge is serviced as a unit with the instrument clus-
ter.
OPERATION
The engine coolant temperature gauge gives an
indication to the vehicle operator of the engine cool-
ant temperature. This gauge is controlled by the
instrument cluster circuit board based upon cluster
programming and electronic messages received by
DRINSTRUMENT CLUSTER 8J - 23

the cluster from the Powertrain Control Module
(PCM) on vehicles equipped with a gasoline engine,
or from the Engine Control Module (ECM) on vehi-
cles equipped with a diesel engine over the Program-
mable Communications Interface (PCI) data bus. The
engine coolant temperature gauge is an air core mag-
netic unit that receives battery current on the instru-
ment cluster electronic circuit board through the
fused ignition switch output (run-start) circuit when-
ever the ignition switch is in the On or Start posi-
tions. The cluster is programmed to move the gauge
needle back to the low end of the scale after the igni-
tion switch is turned to the Off position. The instru-
ment cluster circuitry controls the gauge needle
position and provides the following features:
²Engine Temperature Message- Each time
the cluster receives a message from the PCM or ECM
indicating the engine coolant temperature is between
the low end of normal [about 54É C (130É F) for gas-
oline engines, or about 60É C (140É F) for diesel
engines] and the high end of normal [about 122É C
(252É F) for gasoline engines, or about 116É C (240É
F) for diesel engines], the gauge needle is moved to
the actual relative temperature position on the gauge
scale.
²Engine Temperature Low Message- Each
time the cluster receives a message from the PCM or
ECM indicating the engine coolant temperature is
below the low end of normal [about 54É C (130É F) for
gasoline engines, or about 60É C (140É F) for diesel
engines], the gauge needle is held at the graduation
on the far left end of the gauge scale. The gauge nee-
dle remains at the left end of the gauge scale until
the cluster receives a message from the PCM or ECM
indicating that the engine temperature is above
about 54É C (130É F) for gasoline engines, or about
60É C (140É F) for diesel engines, or until the ignition
switch is turned to the Off position, whichever occurs
first.
²Engine Temperature High Message- Each
time the cluster receives a message from the PCM or
ECM indicating the engine coolant temperature is
above about 122É C (252É F) for gasoline engines, or
about 116É C (240É F) for diesel engines, the gauge
needle is moved into the red zone at the far right end
of gauge scale, the check gauges indicator is illumi-
nated, and a single chime tone is sounded. The gauge
needle remains in the red zone and the check gauges
indicator remains illuminated until the cluster
receives a message from the PCM or ECM indicating
that the engine temperature is below about 122É C
(252É F) for gasoline engines, or about 116É C (240É
F) for diesel engines, or until the ignition switch is
turned to the Off position, whichever occurs first.
The chime tone feature will only repeat during the
same ignition cycle if the check gauges indicator iscycled off and then on again by the appropriate
engine temperature messages from the PCM or ECM.
²Communication Error- If the cluster fails to
receive an engine temperature message, it will hold
the gauge needle at the last indication for about five
seconds or until the ignition switch is turned to the
Off position, whichever occurs first. After five sec-
onds, the cluster will move the gauge needle to the
low end of the gauge scale.
²Actuator Test- Each time the cluster is put
through the actuator test, the engine coolant temper-
ature gauge needle will be swept to several calibra-
tion points on the gauge scale in a prescribed
sequence in order to confirm the functionality of the
gauge and the cluster control circuitry.
On vehicles with a gasoline engine, the PCM con-
tinually monitors the engine coolant temperature
sensor to determine the engine operating tempera-
ture. On vehicles with a diesel engine, the ECM con-
tinually monitors the engine coolant temperature
sensor to determine the engine operating tempera-
ture. The PCM or ECM then sends the proper engine
coolant temperature messages to the instrument
cluster. For further diagnosis of the engine coolant
temperature gauge or the instrument cluster cir-
cuitry that controls the gauge, (Refer to 8 - ELEC-
TRICAL/INSTRUMENT CLUSTER - DIAGNOSIS
AND TESTING). If the instrument cluster turns on
the check gauges indicator due to a high engine tem-
perature gauge reading, it may indicate that the
engine or the engine cooling system requires service.
For proper diagnosis of the engine coolant tempera-
ture sensor, the PCM, the ECM, the PCI data bus, or
the electronic message inputs to the instrument clus-
ter that control the engine coolant temperature
gauge, a DRBIIItscan tool is required. Refer to the
appropriate diagnostic information.
ETC INDICATOR
DESCRIPTION
An Electronic Throttle Control (ETC) indicator is
standard equipment on all gasoline engine instru-
ment clusters. However, on vehicles not equipped
with the optional 5.7 liter gasoline engine, this indi-
cator is electronically disabled. The ETC indicator is
located on the right side of the instrument cluster, to
the right of the engine temperature gauge. The ETC
indicator consists of a stencil-like cutout of the Inter-
national Control and Display Symbol icon for ªElec-
tronic Throttle Controlº in the opaque layer of the
instrument cluster overlay. The dark outer layer of
the overlay prevents the indicator from being clearly
visible when it is not illuminated. A red Light Emit-
ting Diode (LED) behind the cutout in the opaque
8J - 24 INSTRUMENT CLUSTERDR
ENGINE TEMPERATURE GAUGE (Continued)

layer of the overlay causes the icon to appear in red
through the translucent outer layer of the overlay
when the indicator is illuminated from behind by the
LED, which is soldered onto the instrument cluster
electronic circuit board. The ETC indicator is ser-
viced as a unit with the instrument cluster.
OPERATION
The Electronic Throttle Control (ETC) indicator
gives an indication to the vehicle operator when the
ETC system is faulty or inoperative. The ETC indi-
cator is controlled by a transistor on the instrument
cluster circuit board based upon cluster programming
and electronic messages received by the cluster from
the Powertrain Control Module (PCM) over the Pro-
grammable Communications Interface (PCI) data
bus. The ETC indicator Light Emitting Diode (LED)
is completely controlled by the instrument cluster
logic circuit, and that logic will only allow this indi-
cator to operate when the instrument cluster receives
a battery current input on the fused ignition switch
output (run-start) circuit. Therefore, the LED will
always be off when the ignition switch is in any posi-
tion except On or Start. The LED only illuminates
when it is provided a path to ground by the instru-
ment cluster transistor. The instrument cluster will
turn on the ETC indicator for the following reasons:
²Bulb Test- Each time the ignition switch is
turned to the On position the ETC indicator is illu-
minated for about six seconds. The entire six second
bulb test is a function of the PCM.
²ETC Lamp-On Message- Each time the clus-
ter receives a lamp-on message from the PCM, the
ETC indicator will be illuminated. The indicator can
be flashed on and off, or illuminated solid, as dic-
tated by the PCM message. The indicator remains
illuminated solid or continues to flash for about
twelve seconds or until the cluster receives a lamp-off
message from the PCM, whichever is longer. If the
indicator is illuminated solid with the engine run-
ning the vehicle will usually remain drivable. If the
indicator is flashing with the engine running the
vehicle may require towing. A flashing indicator
means the ETC system requires immediate service.
²Communication Error- If the cluster receives
no ETC lamp messages for three consecutive seconds,
the ETC indicator is illuminated. The indicator
remains illuminated until the cluster receives a sin-
gle lamp-off message from the PCM.
²Actuator Test- Each time the cluster is put
through the actuator test, the ETC indicator will be
turned on, then off again during the bulb check por-
tion of the test to confirm the functionality of the
LED and the cluster control circuitry. The actuator
test illumination of the ETC indicator is a function of
the PCM.The PCM continually monitors the ETC system cir-
cuits and sensors to decide whether the system is in
good operating condition. The PCM then sends the
proper lamp-on or lamp-off messages to the instru-
ment cluster. If the PCM sends a lamp-on message
after the bulb test, it indicates that the PCM has
detected a system malfunction and/or that the ETC
system is inoperative. The PCM will store a Diagnos-
tic Trouble Code (DTC) for any malfunction it
detects. Each time the ETC indicator fails to illumi-
nate due to an open or short in the cluster ETC indi-
cator circuit, the cluster sends a message notifying
the PCM of the condition, the instrument cluster and
the PCM will each store a DTC. For proper diagnosis
of the ETC system, the PCM, the PCI data bus, or
the electronic message inputs to the instrument clus-
ter that control the ETC indicator, a DRBIIItscan
tool is required. Refer to the appropriate diagnostic
information.
FUEL GAUGE
DESCRIPTION
A fuel gauge is standard equipment on all instru-
ment clusters. The fuel gauge is located in the lower
left quadrant of the instrument cluster, below the
voltage gauge. The fuel gauge consists of a movable
gauge needle or pointer controlled by the instrument
cluster circuitry and a fixed 90 degree scale on the
cluster overlay that reads left-to-right from ªEº (or
Empty) to ªFº (or Full). An International Control and
Display Symbol icon for ªFuelº is located on the clus-
ter overlay, directly below the right end of the gauge
scale. An arrowhead pointed to the left side of the
vehicle is imprinted on the cluster overlay next to the
ªFuelº icon in the fuel gauge to provide the driver
with a reminder as to the location of the fuel filler
access. On vehicles equipped with a diesel engine,
text that specifies ªDIESEL ONLYº is located across
the fuel gauge below the gauge scale, but above the
hub of the gauge needle. The fuel gauge graphics are
black against a white field except for a single red
graduation at the low end of the gauge scale, making
them clearly visible within the instrument cluster in
daylight. When illuminated from behind by the panel
lamps dimmer controlled cluster illumination lighting
with the exterior lamps turned On, the black graph-
ics appear blue and the red graphics still appear red.
The orange gauge needle is internally illuminated.
Gauge illumination is provided by replaceable incan-
descent bulb and bulb holder units located on the
instrument cluster electronic circuit board. The fuel
gauge is serviced as a unit with the instrument clus-
ter.
DRINSTRUMENT CLUSTER 8J - 25
ETC INDICATOR (Continued)