fuse JEEP GRAND CHEROKEE 2002 WJ / 2.G Service Manual

(2) Reconnect the instrument panel wire harness
connector for the instrument cluster to the connector
receptacle on the back of the instrument cluster
housing (Fig. 7).
(3) Position the lower mounting tabs of the instru-
ment cluster to the mounting holes on the instru-
ment panel structural duct, then tilt the top of the
instrument cluster forward until the upper mounting
tabs are positioned to the mounting holes on the
underside of the instrument cluster hood formation of
the instrument panel top pad.
(4) Install and tighten the two screws that secure
the upper mounting tabs of the instrument cluster to
the underside of the instrument cluster hood forma-
tion of the instrument panel top pad. Tighten the
screws to 2.2 N´m (20 in. lbs.).
(5) Install and tighten the two screws that secure
the lower mounting tabs of the instrument cluster to
the instrument panel structural duct. Tighten the
screws to 2.2 N´m (20 in. lbs.).
(6) Reinstall the cluster bezel onto the instrument
panel. (Refer to 23 - BODY/INSTRUMENT PANEL/
CLUSTER BEZEL - INSTALLATION).
(7) Reconnect the battery negative cable.
ABS INDICATOR
DESCRIPTION
An Anti-lock Brake System (ABS) indicator is stan-
dard equipment on all instrument clusters. The ABS
indicator is located on the lower left edge of the
instrument cluster, to the left of the tachometer. TheABS indicator consists of a International Control and
Display Symbol icon for ªFailure of Anti-lock Braking
Systemº imprinted on an amber lens. The lens is
located behind a cutout 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. The icon appears
silhouetted against an amber field through the trans-
lucent outer layer of the overlay when the indicator
is illuminated from behind by a replaceable incandes-
cent bulb and bulb holder unit located on the instru-
ment cluster electronic circuit board. The ABS
indicator lens is serviced as a unit with the instru-
ment cluster lens, hood and mask unit.
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 Anti-lock Brake
(CAB) over the Programmable Communications
Interface (PCI) data bus. The ABS indicator bulb 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 bat-
tery current input on the fused ignition switch out-
put (run-start) circuit. Therefore, the indicator will
always be off when the ignition switch is in any posi-
tion except On or Start. The bulb only illuminates
when it is provided a path to ground by the instru-
ment cluster transistor. The instrument cluster will
turn on the ABS indicator for the following reasons:
²Bulb Test- Each time the ignition switch is
turned to the On position the CAB sends an elec-
tronic ABS lamp-on message to the cluster which will
illuminate the ABS indicator for about four seconds
as a bulb test. The entire four second bulb test is a
function of the CAB.
²ABS Indicator Lamp-On Message- Each time
the cluster receives an ABS indicator lamp-on mes-
sage from the CAB, the ABS indicator will be illumi-
nated. The indicator remains illuminated until the
cluster receives an ABS indicator 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 ABS indicator lamp-on or lamp-off messages from
the CAB for six consecutive seconds, the ABS indica-
tor is illuminated. The indicator remains illuminated
until the cluster receives a valid lamp-on or lamp-off
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-
Fig. 7 Instrument Cluster Remove/Install
1 - INSTRUMENT PANEL WIRE HARNESS CONNECTOR
2 - INSTRUMENT CLUSTER
WJINSTRUMENT CLUSTER 8J - 13
INSTRUMENT CLUSTER (Continued)

tor will be turned on for the duration of the test to
confirm the functionality of the bulb and the cluster
control circuitry.
²ABS Diagnostic Test- The ABS indicator is
blinked on and off based upon 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
ABS indicator lamp-on or lamp-off messages to the
instrument cluster. If the ABS indicator fails to light
during the bulb test, replace the bulb with a known
good unit. If the CAB sends an ABS indicator
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 indi-
cator fails to illuminate due to an open or short in
the cluster ABS indicator circuit or bulb, 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 anti-lock
brake system, the CAB, the PCI data bus, or the
electronic message inputs to the instrument cluster
that control the ABS indicator, a DRBIIItscan tool is
required. Refer to the appropriate diagnostic infor-
mation.
AIRBAG INDICATOR
DESCRIPTION
An airbag indicator is standard equipment on all
instrument clusters. However, the instrument cluster
is programmed to automatically enable this indicator
only on vehicles equipped with the airbag system,
which is not available in some markets. The airbag
indicator is located on the upper edge of the instru-
ment cluster, between the speedometer and the
tachometer. The airbag indicator consists of the
words ªAIR BAGº imprinted on a red lens. The lens
is located behind a cutout 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. The ªAIR BAGº
text appears silhouetted against a red field through
the translucent outer layer of the overlay when the
indicator is illuminated from behind by a Light Emit-
ting Diode (LED), which is soldered onto the instru-
ment cluster electronic circuit board. The airbag
indicator lens is serviced as a unit with the instru-
ment cluster lens, hood and mask unit.
OPERATION
The airbag indicator gives an indication to the
vehicle operator when the airbag system is faulty or
inoperative. The airbag indicator is controlled by a
transistor on the instrument cluster circuit board
based upon cluster programming and electronic mes-
sages received by the cluster from the Airbag Control
Module (ACM) over the Programmable Communica-
tions Interface (PCI) data bus. The airbag indicator
Light Emitting Diode (LED) 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 current input
on the fused ignition switch output (run-start) cir-
cuit. Therefore, the indicator will always be off when
the ignition switch is in any position except On or
Start. The LED only illuminates when it is switched
to ground by the instrument cluster transistor. The
instrument cluster will turn on the airbag indicator
for the following reasons:
²Bulb Test- Each time the ignition switch is
turned to the On position the ACM sends an elec-
tronic airbag indicator lamp-on message to the clus-
ter which will illuminate the airbag indicator for
about six seconds as a bulb test. The entire six sec-
ond bulb test is a function of the ACM.
²Airbag Indicator Lamp-On Message- Each
time the cluster receives an airbag indicator lamp-on
message from the ACM, the airbag indicator will be
illuminated. The indicator remains illuminated for
about twelve seconds or until the cluster receives an
airbag indicator lamp-off message from the ACM,
whichever is longer.
²Communication Error- If the cluster receives
no airbag indicator lamp-on or lamp-off messages for
six consecutive seconds, the airbag indicator is illu-
minated. The indicator remains illuminated until the
cluster receives a single valid airbag indicator lamp-
off message from the ACM.
²Actuator Test- Each time the cluster is put
through the actuator test, the airbag 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 airbag indicator is also a
function of the ACM.
The ACM continually monitors the airbag system
circuits and sensors to decide whether the system is
in good operating condition. The ACM then sends the
proper airbag indicator lamp-on or lamp-off messages
to the instrument cluster. If the ACM sends an air-
bag indicator lamp-on message after the bulb test, it
indicates that the ACM has detected a system mal-
function. Such a malfunction could mean that the
airbags may not deploy when required, or may
deploy when not required. The ACM will store a
8J - 14 INSTRUMENT CLUSTERWJ
ABS INDICATOR (Continued)

Diagnostic Trouble Code (DTC) for any malfunction it
detects. Each time the airbag indicator fails to illu-
minate due to an open or short in the cluster airbag
indicator circuit, the cluster sends a message notify-
ing the ACM of the condition, then the instrument
cluster and the ACM will each store a DTC. For
proper diagnosis of the airbag system, the ACM, the
PCI data bus, or the electronic message inputs to the
instrument cluster that control the airbag indicator,
a DRBIIItscan tool is required. Refer to the appro-
priate diagnostic information.
BRAKE/PARK BRAKE
INDICATOR
DESCRIPTION
A brake indicator is standard equipment on all
instrument clusters. The brake indicator is located
near the left edge of the instrument cluster, to the
left of the tachometer. There are two versions of the
brake indicator. The version used depends upon the
market for which the vehicle is manufactured. The
version of the brake indicator used for vehicles man-
ufactured for the United States consists of the word
ªBRAKEº imprinted on a red lens. The Rest-Of-World
(ROW) market version of this indicator has two
International Control and Display Symbol icons
imprinted on the red lens; one is the icon for ªBrake
Failureº, and the other is the icon for ªParking
Brakeº. In either case, the lens is located behind a
cutout 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. The ªBRAKEº text or the two icons
appear silhouetted against a red field through the
translucent outer layer of the overlay when the indi-
cator is illuminated from behind by a Light Emitting
Diode (LED), which is soldered onto the instrument
cluster electronic circuit board. The brake indicator
lens is serviced as a unit with the instrument cluster
lens, hood and mask unit.
OPERATION
The brake indicator gives an indication to the vehi-
cle operator when the parking brake is applied, when
the fluid level of the brake hydraulic system is low,
or if there are certain malfunctions of the Anti-lock
Brake System (ABS). This indicator is controlled by a
transistor on the instrument cluster electronic circuit
board based upon cluster programming, electronic
messages received by the cluster from the Controller
Anti-lock Brake (CAB) over the Programmable Com-
munications Interface (PCI) data bus, and a hard
wired input to the cluster from the park brake
switch. The brake indicator Light Emitting Diode(LED) 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 current input on the fused ignition
switch output (run-start) circuit. Therefore, the indi-
cator will always be off when the ignition switch is in
any position except On or Start. The LED only illu-
minates when it is provided a path to ground by the
instrument cluster transistor. The instrument cluster
will turn on the brake indicator for the following rea-
sons:
²Bulb Test- Each time the ignition switch is
turned to the On position the brake indicator is illu-
minated by the instrument cluster for about three
seconds as a bulb test.
²Brake Indicator Lamp-On Message- Each
time the cluster receives a brake indicator lamp-on
message from the CAB, the brake indicator will be
illuminated. The indicator remains illuminated until
the cluster receives a brake indicator lamp-off mes-
sage from the CAB.
²Park Brake Switch Input- Each time the
cluster logic circuit detects ground on the park brake
switch sense circuit (park brake switch closed = park
brake applied or not fully released) the brake indica-
tor is illuminated. The indicator remains illuminated
until the park brake switch sense input to the cluster
is an open circuit (park brake switch open = park
brake fully released), or until the ignition switch is
turned to the Off position, whichever occurs first.
²Communication Error- If the cluster receives
no brake indicator lamp-on or lamp-off messages
from the CAB for six consecutive seconds, the brake
indicator is illuminated. The indicator remains illu-
minated until the cluster receives a single valid
brake indicator lamp-off message from the CAB.
²Actuator Test- Each time the cluster is put
through the actuator test, the brake indicator will be
turned on for the duration of the test to confirm the
functionality of the LED and the cluster control cir-
cuitry.
The park brake switch on the park brake pedal
mechanism provides a hard wired ground input to
the instrument cluster circuitry through the red
brake warning indicator driver circuit whenever the
park brake is applied or not fully released. The CAB
continually monitors the input from the brake fluid
level switch and the circuits of the anti-lock brake
system, then sends the proper brake indicator
lamp-on or lamp-off messages to the instrument clus-
ter. If the CAB sends a brake indicator lamp-on mes-
sage after the bulb test, it indicates that the CAB
has detected a brake hydraulic 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.
WJINSTRUMENT CLUSTER 8J - 15
AIRBAG INDICATOR (Continued)

lens is serviced as a unit with the instrument cluster
lens, hood and mask unit.
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) over the Programmable Communica-
tions Interface (PCI) data bus. The check gauges
indicator Light Emitting Diode (LED) 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 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 three seconds as a bulb test.
²Engine Temperature High/Critical Message
- Each time the cluster receives a message from the
PCM indicating the engine coolant temperature is
high or critical [above about 127É C (261É F) for gas-
oline engines except Gulf Coast Country (GCC), 129É
C (264É F) for GCC gasoline engines, and 118É C
(244É F) for diesel engines], the check gauges indica-
tor is illuminated. The indicator remains illuminated
until the cluster receives a message indicating the
engine coolant temperature is not high or critical
[about 125É C (255É F) or below for all gasoline
engines, or 115É C (239É F) for all diesel engines].
²Engine Oil Pressure Low Message- Each
time the cluster receives a message from the PCM
indicating the engine oil pressure is about 0.28
kg/cm or lower (about 4 psi or lower), the check
gauges indicator is illuminated. The indicator
remains illuminated until the cluster receives a mes-
sage from the PCM indicating that the engine oil
pressure is about 0.56 kg/cm or higher (about 8 psi
or higher). The cluster will only turn the indicator on
in response to an engine oil pressure low message if
the ignition switch is in the On position and the
engine speed is 300 rpm or greater.
²System Voltage Low Message- Each time the
cluster receives a message from the PCM indicating
a low system voltage condition (system voltage is
about eleven volts or lower), the check gauges indica-
tor is illuminated. The indicator remains illuminateduntil the cluster receives a message from the PCM
indicating there is no low system voltage condition
(system voltage is above about eleven volts, but lower
than about sixteen volts).
²System Voltage High Message- Each time
the cluster receives a message from the PCM indicat-
ing a high system voltage condition (system voltage
is about sixteen volts or higher), the check gauges
indicator is illuminated. The indicator remains illu-
minated until the cluster receives a message from
the PCM indicating there is no high system voltage
condition (system voltage is below about sixteen
volts, but higher than about eleven volts).
²Actuator Test- Each time the cluster is put
through the actuator test, the check gauges indicator
will be turned on for the duration of the test to con-
firm the functionality of the LED and the cluster con-
trol circuitry.
The PCM continually monitors the engine temper-
ature, oil pressure, and electrical system voltage,
then sends the proper messages to the instrument
cluster. For further diagnosis of the check gauges
indicator or the instrument cluster circuitry that con-
trols the indicator, (Refer to 8 - ELECTRICAL/IN-
STRUMENT CLUSTER - DIAGNOSIS AND
TESTING). For proper diagnosis of the PCM, 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 information.
COOLANT LOW INDICATOR
DESCRIPTION
A coolant low indicator is only found in the instru-
ment clusters of vehicles equipped with an optional
diesel engine. The coolant low indicator should not be
confused with the coolant level low indication pro-
vided by the Electronic Vehicle Information Center
(EVIC) of vehicles equipped with a gasoline engine,
although they do perform the same function. The
coolant low indicator is located in the lower left cor-
ner of the instrument cluster, to the left of the
tachometer. The coolant low indicator consists of an
International Control and Display Symbol icon for
ªLow Coolantº imprinted on an amber lens. The lens
is located behind a cutout 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. The icon appears
silhouetted against an amber field through the trans-
lucent outer layer of the overlay when the indicator
is illuminated from behind by a replaceable incandes-
cent bulb and bulb holder unit located on the instru-
ment cluster electronic circuit board. When the
WJINSTRUMENT CLUSTER 8J - 17
CHECK GAUGES INDICATOR (Continued)

exterior lighting is turned On, the illumination inten-
sity of the coolant low indicator is dimmable, which
is adjusted using the panel lamps dimmer control
ring on the control stalk of the left multi-function
switch. The coolant low indicator lens is serviced as a
unit with the instrument cluster lens, hood and mask
unit.
OPERATION
The coolant low indicator gives an indication to the
vehicle operator when the diesel engine coolant level
is low. 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 Body Control Module (BCM)
over the Programmable Communications Interface
(PCI) data bus. The coolant low indicator bulb 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 bat-
tery current input on the fused ignition switch out-
put (run-start) circuit. Therefore, the indicator will
always be off when the ignition switch is in any posi-
tion except On or Start. The bulb only illuminates
when it is provided a path to ground by the instru-
ment cluster transistor. The instrument cluster will
turn on the coolant low indicator for the following
reasons:
²Bulb Test- Each time the ignition switch is
turned to the On position the coolant low indicator is
illuminated for about three seconds as a bulb test.
²Coolant Low Indicator Lamp-On Message-
Each time the cluster receives a coolant low indicator
lamp-on message from the BCM indicating the
engine coolant is below the minimum level in the
coolant reservoir, the coolant low indicator will be
illuminated. The indicator remains illuminated until
the cluster receives a coolant low indicator lamp-off
message from the BCM indicating that the engine
coolant level is above the minimum level.
²Actuator Test- Each time the cluster is put
through the actuator test, the coolant low indicator
will be turned on for the duration of the test to con-
firm the functionality of the bulb and the cluster con-
trol circuitry.
The BCM continually monitors the input from the
coolant level switch, then sends the proper coolant
low indicator lamp-on and lamp-off messages to the
instrument cluster. If the coolant low indicator fails
to light during the bulb test, replace the bulb with a
known good unit. For further diagnosis of the coolant
low indicator or the instrument cluster circuitry that
controls the indicator, (Refer to 8 - ELECTRICAL/IN-
STRUMENT CLUSTER - DIAGNOSIS AND TEST-
ING). For proper diagnosis of the coolant level
switch, the BCM, the PCI data bus, or the electronicmessage inputs to the instrument cluster that control
the coolant low 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, but is only functional on vehi-
cles equipped with the optional speed control system.
The cruise indicator is located on the right edge of
the instrument cluster, to the right of the speedome-
ter. The cruise indicator consists of the word
ªCRUISEº imprinted on a blue/green lens. The lens is
located behind a cutout 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. The ªCRUISEº text
appears silhouetted against a blue/green field
through the translucent outer layer of the overlay
when the indicator is illuminated from behind by a
replaceable bulb and bulb holder unit located on the
instrument cluster electronic circuit board. When the
exterior lighting is turned On, the illumination inten-
sity of the cruise indicator is dimmable, which is
adjusted using the panel lamps dimmer control ring
on the control stalk of the left multi-function switch.
The cruise indicator lens is serviced as a unit with
the instrument cluster lens, hood and mask unit.
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 a transistor
on the instrument cluster electronic circuit board
based upon cluster programming and electronic mes-
sages received by the cluster from the Powertrain
Control Module (PCM) over the Programmable Com-
munications Interface (PCI) data bus. The cruise
indicator bulb 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 indicator will always be off when the ignition
switch is in any position except On or Start. The bulb
only illuminates when it is provided a path to ground
by the instrument cluster transistor. The instrument
cluster will turn on the cruise indicator for the fol-
lowing reasons:
²Cruise Indicator Lamp-On Message- Each
time the cluster receives a cruise indicator lamp-on
message from the PCM indicating the speed control
8J - 18 INSTRUMENT CLUSTERWJ
COOLANT LOW INDICATOR (Continued)

the gauge needle at the last indication for about
twelve seconds or until a new engine temperature
message is received, whichever occurs first. After
twelve seconds, the cluster will return the gauge nee-
dle to the low end of the gauge scale.
²Actuator Test- Each time the cluster is put
through the actuator test, the gauge needle will be
swept across the entire gauge scale and back in order
to confirm the functionality of the gauge and the
cluster control circuitry.
The PCM continually monitors the engine coolant
temperature sensor to determine the engine operat-
ing temperature. The PCM then sends the proper
engine coolant temperature messages to the instru-
ment cluster. For further diagnosis of the engine cool-
ant temperature gauge or the instrument cluster
circuitry that controls the gauge, (Refer to 8 - ELEC-
TRICAL/INSTRUMENT CLUSTER - DIAGNOSIS
AND TESTING). If the instrument cluster moves the
engine coolant temperature gauge needle to indicate
a high or critical engine temperature, it may indicate
that the engine or the engine cooling system requires
service. For proper diagnosis of the engine coolant
temperature sensor, the PCM, 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.
FRONT FOG LAMP INDICATOR
DESCRIPTION
A front fog lamp indicator is standard equipment
on all instrument clusters, but is only functional on
vehicles equipped with the optional front fog lamps.
The front fog lamp indicator is located on the left
edge of the instrument cluster, to the left of the
tachometer. The front fog lamp indicator consists of
an International Control and Display Symbol icon for
ªFront Fog Lightº imprinted on a green lens. The
lens is located behind a cutout 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. The icon
appears silhouetted against a green field through the
translucent outer layer of the overlay when the indi-
cator is illuminated from behind by a replaceable
incandescent bulb and bulb holder unit located on
the instrument cluster electronic circuit board. When
the exterior lighting is turned On, the illumination
intensity of the front fog lamp indicator is dimmable,
which is adjusted using the panel lamps dimmer con-
trol ring on the control stalk of the left multi-func-
tion switch. The front fog lamp indicator lens isserviced as a unit with the instrument cluster lens,
hood and mask unit.
OPERATION
The front fog lamp indicator gives an indication to
the vehicle operator whenever the front fog lamps
are illuminated. This indicator is controlled by a
transistor on the instrument cluster circuit board
based upon cluster programming and electronic mes-
sages received by the cluster from the Body Control
Module (BCM) over the Programmable Communica-
tions Interface (PCI) data bus. The front fog lamp
indicator bulb is completely controlled by the instru-
ment cluster logic circuit, and that logic will allow
this indicator to operate whenever the instrument
cluster receives a battery current input on the fused
B(+) circuit. Therefore, the indicator can be illumi-
nated regardless of the ignition switch position. The
bulb only illuminates when it is provided a path to
ground by the instrument cluster transistor. The
instrument cluster will turn on the front fog lamp
indicator for the following reasons:
²Front Fog Lamp Indicator Lamp-On Mes-
sage- Each time the cluster receives a front fog
lamp indicator lamp-on message from the BCM indi-
cating that the front fog lamps are turned On, the
front fog lamp indicator will be illuminated. The indi-
cator remains illuminated until the cluster receives a
front fog lamp indicator lamp-off message from the
BCM.
²Actuator Test- Each time the cluster is put
through the actuator test, the front fog lamp indica-
tor will be turned on for the duration of the test to
confirm the functionality of the bulb and the cluster
control circuitry.
The BCM continually monitors the exterior light-
ing (left multi-function) switch to determine the
proper outputs to the front fog lamp relay. The BCM
then sends the proper front fog lamp indicator
lamp-on and lamp-off messages to the instrument
cluster. If the front fog lamp indicator fails to light
during the actuator test, replace the bulb with a
known good unit. For further diagnosis of the front
fog lamp 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 front fog
lamp system, the BCM, the PCI data bus, or the elec-
tronic message inputs to the instrument cluster that
control the front fog lamp indicator, a DRBIIItscan
tool is required. Refer to the appropriate diagnostic
information.
8J - 20 INSTRUMENT CLUSTERWJ
ENGINE TEMPERATURE GAUGE (Continued)

FUEL GAUGE
DESCRIPTION
A fuel gauge is standard equipment on all instru-
ment clusters. The fuel gauge is located in the lower
left corner of the instrument cluster, to the left of the
tachometer. 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
gauge dial face that reads left-to-right from E (or
Empty) to F (or Full). An International Control and
Display Symbol icon for ªFuelº is located on the
gauge dial face. An arrowhead pointed to the left side
of the vehicle is imprinted next to the ªFuelº icon on
the fuel gauge dial face to provide the driver with a
reminder as to the location of the fuel filler access.
The fuel gauge graphics are either white, gray and
orange against a black gauge dial face (base cluster)
or black and gray against a taupe gauge dial face
(premium cluster), making them clearly visible
within the instrument cluster in daylight. When illu-
minated from behind by the panel lamps dimmer
controlled cluster illumination lighting with the exte-
rior lamps turned On, the base cluster white gauge
graphics appear blue-green and the orange graphics
still appear orange, while the premium cluster taupe
gauge dial face appears blue-green with the black
graphics silhouetted against the illuminated back-
ground. The gray gauge graphics for both versions of
the cluster are not illuminated. The orange gauge
needle in the base cluster gauge is internally illumi-
nated, while the black gauge needle in the premium
cluster gauge is not.
Base cluster gauge illumination is provided by
replaceable incandescent bulb and bulb holder units
located on the instrument cluster electronic circuit
board. Premium cluster gauge illumination is pro-
vided by an integral electro-luminescent lamp that is
serviced as a unit with the instrument cluster. The
fuel gauge is serviced as a unit with the instrument
cluster.
OPERATION
The fuel gauge gives an indication to the vehicle
operator of the level of fuel in the fuel tank. This
gauge is controlled by the instrument cluster circuit
board based upon cluster programming and elec-
tronic messages received by the cluster from the
Powertrain Control Module (PCM) over the Program-
mable Communications Interface (PCI) data bus. The
fuel gauge is an air core magnetic unit that receives
battery current on the instrument cluster electronic
circuit board through the fused ignition switch out-
put (run-start) circuit whenever the ignition switch is
in the On or Start positions. The cluster is pro-
grammed to move the gauge needle back to the lowend of the scale after the ignition switch is turned to
the Off position. The instrument cluster circuitry
controls the gauge needle position and provides the
following features:
²Percent Tank Full Message- Each time the
cluster receives a message from the PCM indicating
the percent tank full, the cluster moves the gauge
needle to the relative fuel level position on the gauge
scale. The PCM applies an algorithm to the input
from the fuel tank sender to dampen gauge needle
movement against the negative effect that fuel slosh-
ing within the fuel tank can have on accurate inputs
to the PCM.
²Less Than 12.5 Percent Tank Full Message-
Each time the cluster receives messages from the
PCM indicating the percent tank full is less than
12.5 (one-eighth), the gauge needle is moved to the
proper position on the gauge scale and the low fuel
indicator is illuminated. The low fuel indicator
remains illuminated until the cluster receives mes-
sages from the PCM indicating that the percent tank
full is greater than 12.5 (one-eighth), or until the
ignition switch is turned to the Off position, which-
ever occurs first.
²Less Than Empty Percent Tank Full Mes-
sage- Each time the cluster receives a message from
the PCM indicating the percent tank full is less than
empty, the gauge needle is moved to the far left (low)
end of the gauge scale and the low fuel indicator is
illuminated immediately. This message would indi-
cate that the fuel tank sender input to the PCM is a
short circuit.
²More Than Full Percent Tank Full Message
- Each time the cluster receives a message from the
PCM indicating the percent tank full is more than
full, the gauge needle is moved to the far left (low)
end of the gauge scale and the low fuel indicator is
illuminated immediately. This message would indi-
cate that the fuel tank sender input to the PCM is an
open circuit.
²Communication Error- If the cluster fails to
receive a percent tank full message, it will hold the
gauge needle at the last indication for about twelve
seconds, until a new message is received, or until the
ignition switch is turned to the Off position, which-
ever occurs first. After twelve seconds, the cluster
will return the gauge needle to the low end of the
gauge scale.
²Actuator Test- Each time the cluster is put
through the actuator test, the gauge needle will be
swept across the entire gauge scale and back in order
to confirm the functionality of the gauge and the
cluster control circuitry.
The PCM continually monitors the fuel tank
sender to determine the fuel level. The PCM then
applies an algorithm to the input and sends the
WJINSTRUMENT CLUSTER 8J - 21

proper percent tank full messages to the instrument
cluster. For further diagnosis of the fuel gauge or the
instrument cluster circuitry that controls the gauge,
(Refer to 8 - ELECTRICAL/INSTRUMENT CLUS-
TER - DIAGNOSIS AND TESTING). For proper
diagnosis of the fuel tank sender, the PCM, the PCI
data bus, or the electronic message inputs to the
instrument cluster that control the fuel gauge, a
DRBIIItscan tool is required. Refer to the appropri-
ate diagnostic information.
HIGH BEAM INDICATOR
DESCRIPTION
A high beam indicator is standard equipment on
all instrument clusters. The high beam indicator is
located near the upper edge of the instrument clus-
ter, between the tachometer and the speedometer.
The high beam indicator consists of an International
Control and Display Symbol icon for ªHigh Beamº
imprinted on a blue lens. The lens is located behind a
cutout 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. The icon appears silhouetted against a
blue field through the translucent outer layer of the
overlay when the indicator is illuminated from
behind by a replaceable incandescent bulb and bulb
holder unit located on the instrument cluster elec-
tronic circuit board. When the exterior lighting is
turned On, the illumination intensity of the high
beam indicator is dimmable, which is adjusted using
the panel lamps dimmer control ring on the control
stalk of the left multi-function switch. The high beam
indicator lens is serviced as a unit with the instru-
ment cluster lens, hood and mask unit.
OPERATION
The high beam indicator gives an indication to the
vehicle operator whenever the headlamp high beams
are illuminated. This indicator is controlled by a
transistor on the instrument cluster electronic circuit
board based upon cluster programming and elec-
tronic messages received by the cluster from the
Body Control Module (BCM) over the Programmable
Communications Interface (PCI) data bus. The high
beam indicator bulb 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 B(+) circuit. Therefore, the indicator can be
illuminated regardless of the ignition switch position.
The LED only illuminates when it is provided a path
to ground by the instrument cluster transistor. Theinstrument cluster will turn on the high beam indi-
cator for the following reasons:
²High Beam Indicator Lamp-On Message-
Each time the cluster receives a high beam indicator
lamp-on message from the BCM indicating that the
headlamp high beams are turned On, the high beam
indicator will be illuminated. The indicator remains
illuminated until the cluster receives a high beam
indicator lamp-off message from the BCM.
²Actuator Test- Each time the cluster is put
through the actuator test, the high beam indicator
will be turned on for the duration of the test to con-
firm the functionality of the bulb and the cluster con-
trol circuitry.
The BCM continually monitors the exterior light-
ing (left multi-function) switch to determine the
proper outputs to the headlamp low beam and high
beam relays. The BCM then sends the proper high
beam indicator lamp-on and lamp-off messages to the
instrument cluster. If the high beam indicator fails to
light during the actuator test, replace the bulb with a
known good unit. For further diagnosis of the high
beam 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 headlamp
system, the BCM, the PCI data bus, or the electronic
message inputs to the instrument cluster that control
the high beam indicator, a DRBIIItscan tool is
required. Refer to the appropriate diagnostic infor-
mation.
LOW FUEL INDICATOR
DESCRIPTION
A low fuel indicator is standard equipment on all
instrument clusters. The low fuel indicator is located
near the left edge of the instrument cluster, to the left
of the tachometer. The low fuel indicator consists of an
International Control and Display Symbol icon for
ªFuelº imprinted on an amber lens. The lens is located
behind a cutout in the opaque layer of the instrument
cluster overlay. The dark outer layer of the overlay
prevents the icon from being clearly visible when the
indicator is not illuminated. The icon appears silhou-
etted against an amber field through the translucent
outer layer of the overlay when the indicator is illumi-
nated from behind by a replaceable incandescent bulb
and bulb holder unit located on the instrument cluster
electronic circuit board. When the exterior lighting is
turned On, the illumination intensity of the low fuel
indicator is dimmable, which is adjusted using the
panel lamps dimmer control ring on the control stalk
of the left multi-function switch. The low fuel indica-
8J - 22 INSTRUMENT CLUSTERWJ
FUEL GAUGE (Continued)

tor lens is serviced as a unit with the instrument clus-
ter lens, hood and mask unit.
OPERATION
The low fuel indicator gives an indication to the
vehicle operator when the level of fuel in the fuel
tank becomes low. This indicator is controlled by a
transistor on the instrument cluster electronic circuit
board based upon cluster programming and elec-
tronic messages received by the cluster from the
Powertrain Control Module (PCM) over the Program-
mable Communications Interface (PCI) data bus. The
low fuel indicator bulb is completely controlled by the
instrument cluster logic circuit, and that logic will
only allow this indicator to operate when the instru-
ment cluster receives a battery current 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 bulb only illuminates when it is switched to
ground by the instrument cluster transistor. The
instrument cluster will turn on the low fuel indicator
for the following reasons:
²Bulb Test- Each time the ignition switch is
turned to the On position the low fuel indicator is
illuminated for about three seconds as a bulb test.
²Less Than 12.5 Percent Tank Full Message-
Each time the cluster receives a message from the
PCM indicating that the percent tank full is less
than about 12.5 (one-eighth), the low fuel indicator is
illuminated. The indicator remains illuminated until
the cluster receives messages from the PCM indicat-
ing that the percent tank full has increased to
greater than about 12.5 (one-eighth). The PCM
applies an algorithm to the input from the fuel tank
sender to dampen the illumination of the low fuel
indicator against the negative effect that fuel slosh-
ing within the fuel tank can have on accurate inputs
to the PCM.
²Less Than Empty Percent Tank Full Mes-
sage- Each time the cluster receives a message from
the PCM indicating the percent tank full is less than
empty, the low fuel indicator is illuminated immedi-
ately. This message would indicate that the fuel tank
sender input to the PCM is a short circuit.
²More Than Full Percent Tank Full Message
- Each time the cluster receives a message from the
PCM indicating the percent tank full is more than
full, the low fuel indicator is illuminated immedi-
ately. This message would indicate that the fuel tank
sender input to the PCM is an open circuit.
²Communication Error- If the cluster fails to
receive a percent tank full message for more than
about twelve seconds, the cluster control circuitry
will illuminate the low fuel indicator until a new per-
cent tank full message is received.²Actuator Test- Each time the cluster is put
through the actuator test, the low fuel indicator will
be turned on for the duration of the test to confirm
the functionality of the bulb and the cluster control
circuitry.
The PCM continually monitors the fuel tank
sender input to determine the fuel level. The PCM
then applies an algorithm to the input and sends the
proper percent tank full messages to the instrument
cluster. If the low fuel indicator fails to light during
the bulb test, replace the bulb with a known good
unit. For further diagnosis of the low fuel indicator
or the instrument cluster circuitry that controls the
indicator, (Refer to 8 - ELECTRICAL/INSTRUMENT
CLUSTER - DIAGNOSIS AND TESTING). For
proper diagnosis of the fuel tank sender, the PCM,
the PCI data bus, or the electronic message inputs to
the instrument cluster that control the low fuel indi-
cator, a DRBIIItscan tool is required. Refer to the
appropriate diagnostic information.
MALFUNCTION INDICATOR
LAMP (MIL)
DESCRIPTION
A Malfunction Indicator Lamp (MIL) is standard
equipment on all instrument clusters. The MIL is
located near the right edge of the instrument cluster,
to the right of the speedometer. The MIL consists of
an International Control and Display Symbol icon for
ªEngineº imprinted on an amber lens. The lens is
located behind a cutout in the opaque layer of the
instrument cluster overlay. The dark outer layer of
the overlay prevents the icon from being clearly vis-
ible when the indicator is not illuminated. The icon
appears silhouetted against an amber field through
the translucent outer layer of the overlay when the
indicator is illuminated from behind by a replaceable
incandescent bulb and bulb holder unit located on
the instrument cluster electronic circuit board. The
MIL lens is serviced as a unit with the instrument
cluster lens, hood and mask unit.
OPERATION
The Malfunction Indicator Lamp (MIL) gives an
indication to the vehicle operator when the Power-
train Control Module (PCM) has recorded a Diagnos-
tic Trouble Code (DTC) for an On-Board Diagnostics
II (OBDII) emissions-related circuit or component
malfunction. This indicator is controlled by a transis-
tor on the instrument cluster electronic circuit board
based upon cluster programming and electronic mes-
sages received by the cluster from the PCM over the
Programmable Communications Interface (PCI) data
bus. The MIL bulb is completely controlled by the
WJINSTRUMENT CLUSTER 8J - 23
LOW FUEL INDICATOR (Continued)

instrument cluster logic circuit, and that logic will
only allow this indicator to operate when the instru-
ment cluster receives a battery current 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 bulb only illuminates when it is provided a path
to ground by the instrument cluster transistor. The
instrument cluster will turn on the MIL for the fol-
lowing reasons:
²Bulb Test- Each time the ignition switch is
turned to the On position the MIL is illuminated for
about three seconds as a bulb test.
²MIL Lamp-On Message- Each time the clus-
ter receives a MIL lamp-on message from the PCM,
the indicator will be illuminated. The indicator can
be flashed on and off, or illuminated solid, as dic-
tated by the PCM message. For some DTC's, if a
problem does not recur, the PCM will send a MIL
lamp-off message automatically. Other DTC's may
require that a fault be repaired and the PCM be
reset before a MIL lamp-off message will be sent. For
more information on the PCM and the DTC set and
reset parameters, (Refer to 25 - EMISSIONS CON-
TROL - OPERATION).
²Communication Error- If the cluster receives
no MIL lamp-on or lamp-off messages from the PCM
for twenty consecutive seconds, the MIL is illumi-
nated by the instrument cluster. The indicator
remains controlled and illuminated by the cluster
until a valid MIL lamp-on or lamp-off message is
received from the PCM.
²Actuator Test- Each time the cluster is put
through the actuator test, the MIL will be turned on
for the duration of the test to confirm the functional-
ity of the bulb and the cluster control circuitry.
The PCM continually monitors each of the many
fuel and emissions system circuits and sensors to
decide whether the system is in good operating con-
dition. The PCM then sends the proper MIL lamp-on
or lamp-off messages to the instrument cluster. If the
MIL fails to light during the bulb test, replace the
bulb with a known good unit. For further diagnosis of
the MIL or the instrument cluster circuitry that con-
trols the indicator, (Refer to 8 - ELECTRICAL/IN-
STRUMENT CLUSTER - DIAGNOSIS AND
TESTING). If the instrument cluster turns on the
MIL after the bulb test, it may indicate that a mal-
function has occurred and that the fuel and emis-
sions system may require service. For proper
diagnosis of the fuel and emissions systems, the
PCM, the PCI data bus, or the electronic message
inputs to the instrument cluster that control the
MIL, a DRBIIItscan tool is required. Refer to the
appropriate diagnostic information.ODOMETER
DESCRIPTION
An odometer and trip odometer are standard
equipment in all instrument clusters. The odometer
and trip odometer information are displayed in a
common electronic, blue-green Vacuum-Fluorescent
Display (VFD), which is located in the lower edge of
the speedometer dial face in the instrument cluster
and, when illuminated, is visible through a small
window cutout in the gauge overlay. However, the
odometer and trip odometer information are not dis-
played simultaneously. The trip odometer reset
switch on the instrument cluster electronic circuit
board toggles the display between odometer and trip
odometer modes by depressing the odometer/trip
odometer switch button that extends through the
lower edge of the cluster lens to the right of the
speedometer.
All odometer and trip odometer distance informa-
tion is stored in the instrument cluster memory. This
distance information can be increased when the
proper inputs are provided to the instrument cluster,
but the distance information cannot be decreased.
The odometer can display values up to 999,999 kilo-
meters (999,999 miles). The odometer will not roll
over, but will latch at the maximum value. The trip
odometer can display values up to 999.9 kilometers
(999.9 miles) before it rolls over to zero. The odome-
ter display does not have a decimal point and will
not show values less than a full unit (kilometer or
mile), the trip odometer display does have a decimal
point and will show tenths of a unit (kilometer or
mile).
The unit of measure for the odometer and trip
odometer display is not shown in the VFD. The unit
of measure for the odometer/trip odometer is selected
at the time that the instrument cluster is manufac-
tured, and cannot be changed. If the instrument clus-
ter has a kilometers-per-hour primary speedometer
scale, the odometer/trip odometer registers kilome-
ters; and, if the cluster features a miles-per-hour pri-
mary speedometer scale, the odometer/trip odometer
registers miles.
During daylight hours (exterior lamps Off) the
VFD is illuminated at full brightness for clear visibil-
ity. At night (exterior lamps are On) the instrument
cluster converts an electronic dimming level message
received from the Body Control Module (BCM) over
the Programmable Communications Interface (PCI)
data bus to a digital dimming level signal for control-
ling the lighting level of the VFD. However, a
ªParadeº mode position of the panel lamps dimmer
control ring on the control stalk of the left (lighting)
multi-function switch allows the VFD to be illumi-
8J - 24 INSTRUMENT CLUSTERWJ
MALFUNCTION INDICATOR LAMP (MIL) (Continued)