Bus switch JEEP LIBERTY 2002 KJ / 1.G Owner's Guide
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Page 411 of 1803
fused ignition switch output (run-start) circuit
between the JB and the ignition switch as required.
(6) With the ignition switch still in the On posi-
tion, check for battery voltage at the fused ignition
switch output (run-start) circuit cavity of the instru-
ment panel wire harness connector for the instru-
ment cluster. If OK, go to Step 7. If not OK, repair
the open fused ignition switch output circuit (run-
start) between the instrument cluster and the JB as
required.
(7) Turn the ignition switch to the Off position.
Disconnect and isolate the battery negative cable.
Check for continuity between the ground circuit cav-
ity of the instrument panel wire harness connector
for the instrument cluster and a good ground. There
should be continuity. If OK, refer to ACTUATOR
TEST . If not OK, repair the open ground circuit
between the instrument cluster and ground (G202) as
required.
ACTUATOR TEST
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE SUPPLEMENTAL RESTRAINT
SYSTEM BEFORE ATTEMPTING ANY STEERING
WHEEL, STEERING COLUMN, DRIVER AIRBAG,
PASSENGER AIRBAG, SEAT BELT TENSIONER,
FRONT IMPACT SENSORS, SIDE CURTAIN AIRBAG,
OR INSTRUMENT PANEL COMPONENT DIAGNOSIS
OR SERVICE. DISCONNECT AND ISOLATE THE
BATTERY NEGATIVE (GROUND) CABLE, THEN
WAIT TWO MINUTES FOR THE SYSTEM CAPACI-
TOR TO DISCHARGE BEFORE PERFORMING FUR-
THER DIAGNOSIS OR SERVICE. THIS IS THE ONLY
SURE WAY TO DISABLE THE SUPPLEMENTAL
RESTRAINT SYSTEM. FAILURE TO TAKE THE
PROPER PRECAUTIONS COULD RESULT IN ACCI-
DENTAL AIRBAG DEPLOYMENT AND POSSIBLE
PERSONAL INJURY.
The instrument cluster actuator test will put the
instrument cluster into its self-diagnostic mode. In
this mode the instrument cluster can perform a self-
diagnostic test that will confirm that the instrument
cluster circuitry, the gauges, the PCI data bus mes-
sage controlled indicator lamps, and the chime tone
generator are capable of operating as designed. Dur-
ing the actuator test the instrument cluster circuitry
will sound the chime tone generator, position each of
the gauge needles at various specified calibration
points, illuminate each of the segments in the Vacu-um-Fluorescent Display (VFD), and turn all of the
PCI data bus message-controlled indicators on and
off again.
Successful completion of the actuator test will con-
firm that the instrument cluster is operational. How-
ever, there may still be a problem with the PCI data
bus, the Powertrain Control Module (PCM), the Air-
bag Control Module (ACM), the Sentry Key Immobi-
lizer Module (SKIM), or the inputs to one of these
electronic control modules. Use a DRBIIItscan tool
to diagnose these components. Refer to the appropri-
ate diagnostic information.
(1) Begin the test with the ignition switch in the
Off position.
(2) Depress the odometer/trip odometer switch but-
ton.
(3) While still holding the odometer/trip odometer
switch button depressed, turn the ignition switch to
the On position, but do not start the engine.
(4) Release the odometer/trip odometer switch but-
ton.
(5) The instrument cluster will automatically
begin the actuator test sequence, as follows:
(a) The cluster will turn on, then off again each
of the PCI data bus message controlled indicators
to confirm the functionality of the indicator and
the cluster control circuitry:
(b) The cluster will sweep the needles for each of
the gauges to several calibration points in sequence
to confirm the functionality of the gauge and the
cluster control circuitry:
(c) The cluster will sequentially step the odome-
ter/trip odometer VFD display from all ones
( 111111 )through all nines (999999) to confirm the
functionality of all VFD segments and their control
circuitry, then display the software version number.
(d) The cluster will generate five (5) chime tones
to confirm the functionality of the chime tone gen-
erator and the chime control circuitry.
(6) The actuator test is now completed. The instru-
ment cluster will automatically exit the self-diagnos-
tic mode and return to normal operation at the
completion of the test, if the ignition switch is turned
to the Off position during the test, or if an engine
rpm message indicating that the engine is running is
received from the PCM over the PCI data bus during
the test.
(7) Go back to Step 1 to repeat the test, if
required.
8J - 8 INSTRUMENT CLUSTERKJ
INSTRUMENT CLUSTER (Continued)
Page 414 of 1803
(2) With the bulb holder fully seated against the
cluster electronic circuit board, turn the bulb holder
clockwise about sixty degrees to lock it into place.
(3) Reinstall the instrument cluster onto the
instrument panel. (Refer to 8 - ELECTRICAL/IN-
STRUMENT CLUSTER - INSTALLATION).
(4) Reconnect the battery negative cable.
CLUSTER LENS, HOOD, AND MASK
(1) Position the cluster lens, hood, and mask unit
over the face of the instrument cluster (Fig. 5). Be
certain that the odometer/trip odometer switch but-
ton is inserted through the proper clearance holes in
the mask and the lens.
(2) From the back of the instrument cluster, install
and tighten the six screws that secure the rear cover
and the lens, hood, and mask unit to the cluster
housing. Tighten the screws to 1 N´m (10 in. lbs.).
(3) Reinstall the instrument cluster onto the
instrument panel. (Refer to 8 - ELECTRICAL/IN-
STRUMENT CLUSTER - INSTALLATION).
(4) Reconnect the battery negative cable.
INSTALLATION
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE SUPPLEMENTAL RESTRAINT
SYSTEM BEFORE ATTEMPTING ANY STEERING
WHEEL, STEERING COLUMN, DRIVER AIRBAG,
PASSENGER AIRBAG, SEAT BELT TENSIONER,
FRONT IMPACT SENSORS, SIDE CURTAIN AIRBAG,
OR INSTRUMENT PANEL COMPONENT DIAGNOSIS
OR SERVICE. DISCONNECT AND ISOLATE THE
BATTERY NEGATIVE (GROUND) CABLE, THEN
WAIT TWO MINUTES FOR THE SYSTEM CAPACI-
TOR TO DISCHARGE BEFORE PERFORMING FUR-
THER DIAGNOSIS OR SERVICE. THIS IS THE ONLY
SURE WAY TO DISABLE THE SUPPLEMENTAL
RESTRAINT SYSTEM. FAILURE TO TAKE THE
PROPER PRECAUTIONS COULD RESULT IN ACCI-
DENTAL AIRBAG DEPLOYMENT AND POSSIBLE
PERSONAL INJURY.
(1) Position the instrument cluster to the instru-
ment panel.
(2) Reconnect the instrument panel wire harness
connector for the cluster to the cluster connector
receptacle.
(3) Position the instrument cluster into the instru-
ment panel.
(4) Install and tighten the four screws that secure
the instrument cluster to the instrument panel (Fig.
3). Tighten the screws to 2 N´m (17 in. lbs.).
(5) Reinstall the cluster bezel onto the instrument
panel. (Refer to 23 - BODY/INSTRUMENT PANEL/
CLUSTER BEZEL - INSTALLATION).
(6) Reconnect the battery negative cable.NOTE: Some of the indicators in this instrument
cluster are self configured or automatically config-
ured when the cluster is connected to the vehicle
electrical system. This feature allows those indica-
tors to be enabled for compatibility with certain
optional equipment. However, if an instrument clus-
ter was previously connected to another vehicle
with different equipment options than the current
vehicle, some of the automatically configured indi-
cator settings may have to be disabled using a
DRBIIITscan tool. Refer to the appropriate diagnos-
tic information.
ABS INDICATOR
DESCRIPTION
An Antilock Brake System (ABS) indicator is stan-
dard equipment on all instrument clusters. However,
the instrument cluster is programmed to automati-
cally enable this indicator only on vehicles equipped
with the optional antilock brake system. The ABS
indicator is located above the engine temperature
gauge and to the right of the speedometer in the
instrument cluster. The ABS indicator consists of a
stencil-like cutout of the International Control and
Display Symbol icon for ªFailure of Anti-lock Braking
Systemº in the opaque layer of the instrument clus-
ter overlay. The dark outer layer of the overlay pre-
vents 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 it is
illuminated from behind by the LED, which is sol-
dered onto the instrument cluster electronic circuit
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
KJINSTRUMENT CLUSTER 8J - 11
INSTRUMENT CLUSTER (Continued)
Page 415 of 1803
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 three 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
six consecutive seconds, the ABS indicator is illumi-
nated. 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 each store a Diag-
nostic 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 diag-
nosis of the antilock brake system, the CAB, the PCI
data bus, or the message inputs to the instrument
cluster that control the ABS indicator, a DRBIIIt
scan tool is required. Refer to the appropriate diag-
nostic information.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 above the fuel gauge and to the
left of the tachometer in the instrument cluster. The
airbag indicator consists of a stencil-like cutout of the
words ªAIR BAGº in the opaque layer of the instru-
ment cluster overlay. The dark outer layer of the
overlay prevents the indicator from being clearly vis-
ible when it is not illuminated. A red Light Emitting
Diode (LED) behind the cutout in the opaque layer of
the overlay causes the ªAIR BAGº text to appear in
red through the translucent outer layer of the over-
lay when it is illuminated from behind by the LED,
which is soldered onto the instrument cluster elec-
tronic circuit board. The airbag indicator is serviced
as a unit with the instrument cluster.
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 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 airbag indicator
for the following reasons:
²Bulb Test- Each time the ignition switch is
turned to the On position the airbag indicator is illu-
minated for about six seconds. The entire six second
bulb test is a function of the ACM.
²ACM Lamp-On Message- Each time the clus-
ter receives a 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 a lamp-off message from the
ACM, whichever is longer.
²Communication Error- If the cluster receives
no airbag messages for six consecutive seconds, the
airbag indicator is illuminated. The indicator
8J - 12 INSTRUMENT CLUSTERKJ
ABS INDICATOR (Continued)
Page 416 of 1803
remains illuminated until the cluster receives a sin-
gle 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 a function
of the instrument cluster.
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 lamp-on or lamp-off messages to the instru-
ment cluster. If the ACM sends a lamp-on message
after the bulb test, it indicates that the ACM has
detected a system malfunction and/or that the air-
bags and driver seat belt tensioner may not deploy
when required, or may deploy when not required.
The ACM will store a Diagnostic Trouble Code (DTC)
for any malfunction it detects. Each time the airbag
indicator fails to illuminate due to an open or short
in the cluster airbag indicator circuit, the cluster
sends a message notifying the ACM of the condition,
then the instrument cluster and the ACM will each
store a DTC. For proper diagnosis of the airbag sys-
tem, the ACM, the PCI data bus, or the message
inputs to the instrument cluster that control the air-
bag indicator, a DRBIIItscan tool is required. Refer
to the appropriate diagnostic information.
BRAKE/PARK BRAKE
INDICATOR
DESCRIPTION
A brake indicator is standard equipment on all
instrument clusters. The brake indicator is located
near the lower edge of the tachometer dial face in the
instrument cluster. The brake indicator consists of
stencil-like cutouts of the word ªBRAKEº and the
International Control and Display Symbol icon for
ªBrake Failureº in the opaque layer of the instru-
ment cluster overlay. The dark outer layer of the
overlay prevents the indicator from being clearly vis-
ible when it is not illuminated. A red Light Emitting
Diode (LED) behind the cutout in the opaque layer of
the overlay causes the ªBRAKEº text and 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 brake
indicator is serviced as a unit with the instrument
cluster.
OPERATION
The brake indicator gives an indication to the vehi-
cle operator when the parking brake is applied, when
there are certain brake hydraulic system malfunc-
tions as indicated by a low brake hydraulic fluid level
condition, or when the brake fluid level switch is dis-
connected. On models equipped with an optional
Antilock Brake System (ABS), the brake indicator
can also give an indication when certain faults are
detected in the 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
Antilock Brake (CAB) over the Programmable Com-
munications Interface (PCI) data bus (ABS only), and
hard wired inputs from the park brake switch and
the brake fluid level 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) cir-
cuit. 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 brake indicator
for the following reasons:
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 Lamp-On Message- Each time the
cluster receives a lamp-on message from the CAB,
the brake 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.
²Park Brake Switch Input- Each time the
cluster detects ground on the park brake switch
sense circuit (park brake switch closed = park brake
applied or not fully released) the brake indicator 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.
²Brake Fluid Level Switch Input- Each time
the cluster detects ground on the red brake warning
indicator driver circuit (brake fluid level switch
closed = brake hydraulic system fluid level low) the
brake indicator is illuminated solid. The indicator
remains illuminated until the status of the red brake
warning indicator driver input to the cluster is off
(brake fluid level switch off = brake hydraulic system
KJINSTRUMENT CLUSTER 8J - 13
AIRBAG INDICATOR (Continued)
Page 417 of 1803
fluid level is not low), or until the ignition switch is
turned to the Off position, whichever occurs first.
²Brake Fluid Level Switch Input Fault- The
brake fluid level switch also features a 1 kilohm
diagnostic resistor connected in parallel between the
switch input and output to provide the cluster with
verification that the red brake warning indicator
driver circuit is not open. If the cluster does not see a
proper input on the red brake warning indicator
driver circuit, it will turn on the brake indicator. The
indicator remains illuminated until the red brake
warning indicator driver circuit fault is resolved, 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 brake indi-
cator will be turned on, then off again during the
bulb check portion of the test to confirm the function-
ality of the LED and the cluster control circuitry.
The park brake switch on the park brake pedal
mechanism provides a hard wired ground input to
the instrument cluster circuitry through the park
brake switch sense circuit whenever the park brake
is applied or not fully released. The brake fluid level
switch on the brake master cylinder reservoir pro-
vides a hard wired ground input to the instrument
cluster circuitry through the red brake warning indi-
cator driver circuit whenever the fluid level in the
reservoir becomes low. On models equipped with the
optional ABS, the CAB sends the proper lamp-on or
lamp-off messages to the instrument cluster. If the
CAB sends a lamp-on message after the bulb test, it
indicates that the CAB has detected a brake hydrau-
lic system malfunction and/or that the ABS system
has become inoperative. The CAB will store a Diag-
nostic Trouble Code (DTC) for any malfunction it
detects.
For further diagnosis of the brake indicator or the
instrument cluster circuitry that controls the LED,
(Refer to 8 - ELECTRICAL/INSTRUMENT CLUS-
TER - DIAGNOSIS AND TESTING). The park brake
switch input to the instrument cluster can be diag-
nosed using conventional diagnostic tools and meth-
ods. For proper diagnosis of the brake fluid level
switch input to the instrument cluster, the antilock
brake system, the CAB, the PCI data bus, or the
electronic message inputs to the instrument cluster
that control the brake indicator, a DRBIIItscan tool
is required. Refer to the appropriate diagnostic infor-
mation.
DIAGNOSIS AND TESTING - BRAKE INDICATOR
The diagnosis found here addresses an inoperative
brake indicator condition. If there are problems with
several indicators in the instrument cluster, (Refer to
8 - ELECTRICAL/INSTRUMENT CLUSTER - DIAG-NOSIS AND TESTING). If the brake indicator stays
on with the ignition switch in the On position and
the park brake released, or comes on while driving,
(Refer to 5 - BRAKES - DIAGNOSIS AND TEST-
ING). If no brake system problem is found, the fol-
lowing procedures will help to locate a shorted or
open circuit, or a faulty park brake switch input.
Refer to the appropriate wiring information. The wir-
ing information includes wiring diagrams, proper
wire and connector repair procedures, details of wire
harness routing and retention, connector pin-out
information and location views for the various wire
harness connectors, splices and grounds.
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE SUPPLEMENTAL RESTRAINT
SYSTEM BEFORE ATTEMPTING ANY STEERING
WHEEL, STEERING COLUMN, DRIVER AIRBAG,
PASSENGER AIRBAG, SEAT BELT TENSIONER,
FRONT IMPACT SENSORS, SIDE CURTAIN AIRBAG,
OR INSTRUMENT PANEL COMPONENT DIAGNOSIS
OR SERVICE. DISCONNECT AND ISOLATE THE
BATTERY NEGATIVE (GROUND) CABLE, THEN
WAIT TWO MINUTES FOR THE SYSTEM CAPACI-
TOR TO DISCHARGE BEFORE PERFORMING FUR-
THER DIAGNOSIS OR SERVICE. THIS IS THE ONLY
SURE WAY TO DISABLE THE SUPPLEMENTAL
RESTRAINT SYSTEM. FAILURE TO TAKE THE
PROPER PRECAUTIONS COULD RESULT IN ACCI-
DENTAL AIRBAG DEPLOYMENT AND POSSIBLE
PERSONAL INJURY.
INDICATOR ILLUMINATES DURING BULB TEST, BUT DOES
NOT WHEN PARK BRAKE APPLIED
(1) Disconnect and isolate the battery negative
cable. Disconnect the front body wire harness connec-
tor for the park brake switch from the switch termi-
nal. Apply the parking brake. Check for continuity
between the park brake switch terminal and a good
ground. There should be continuity. If OK, go to Step
2. If not OK, replace the faulty park brake switch.
(2) Disconnect the instrument panel wire harness
connector for the instrument cluster from the cluster
connector receptacle. Check for continuity between
the park brake switch sense circuit cavities of the
front body wire harness connector for the park brake
switch and the instrument panel wire harness con-
nector for the instrument cluster. There should be
continuity. If not OK, repair the open park brake
switch sense circuit between the park brake switch
and the instrument cluster as required.
INDICATOR REMAINS ILLUMINATED - BRAKE SYSTEM
CHECKS OK
(1) Disconnect and isolate the battery negative
cable. Disconnect the front body wire harness connec-
8J - 14 INSTRUMENT CLUSTERKJ
BRAKE/PARK BRAKE INDICATOR (Continued)
Page 418 of 1803
tor for the park brake switch from the switch termi-
nal. Check for continuity between the terminal of the
park brake switch and a good ground. There should
be no continuity with the park brake released, and
continuity with the park brake applied. If OK, go to
Step 2. If not OK, replace the faulty park brake
switch.
(2) Disconnect the instrument panel wire harness
connector for the instrument cluster from the cluster
connector receptacle. Check for continuity between
the park brake switch sense circuit cavity of the front
body wire harness connector for the park brake
switch and a good ground. There should be no conti-
nuity. If not OK, repair the shorted park brake
switch sense circuit between the park brake switch
and the instrument cluster as required.
CHARGING INDICATOR
DESCRIPTION
A charging indicator is standard equipment on all
instrument clusters. The charging indicator is located
above the engine temperature gauge and to the right
of the speedometer in the instrument cluster. The
charging indicator consists of a stencil-like cutout of
the International Control and Display Symbol icon
for ªBattery Charging Conditionº 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 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
charging indicator is serviced as a unit with the
instrument cluster.
OPERATION
The charging indicator gives an indication to the
vehicle operator when the electrical system voltage is
too low or too high. This indicator is controlled by a
transistor on the instrument cluster electronic circuit
board based upon the 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
charging 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 bat-
tery current input on the fused ignition switch out-
put (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 charging indicator for the following rea-
sons:
²Bulb Test- Each time the ignition switch is
turned to the On position the charging indicator is
illuminated by the instrument cluster for about three
seconds as a bulb test.
²Charge Fail Message- Each time the cluster
receives a charge fail message from the PCM (system
voltage is nine volts or lower, the charging indicator
will be illuminated. The indicator remains illumi-
nated until the cluster receives a message from the
PCM indicating there is no charge fail condition (sys-
tem voltage is twelve volts or higher, but lower than
sixteen volts), or until the ignition switch is turned to
the Off position, whichever occurs first.
²Voltage High Message- Each time the cluster
receives a message from the PCM indicating a volt-
age high condition (system voltage is sixteen volts or
higher), the lamp will be illuminated. The lamp
remains illuminated until the cluster receives a mes-
sage from the PCM indicating there is no voltage
high condition (system voltage is lower than sixteen
volts, but higher than nine volts), or until the igni-
tion switch is turned to the Off position, whichever
occurs first.
²Actuator Test- Each time the cluster is put
through the actuator test, the charging 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 PCM continually monitors the electrical sys-
tem voltage to control the generator output. The
PCM then sends the proper system voltage messages
to the instrument cluster. If the instrument cluster
turns on the indicator after the bulb test, it may
indicate that the charging system requires service.
For further diagnosis of the charging indicator or the
instrument cluster circuitry that controls the indica-
tor, (Refer to 8 - ELECTRICAL/INSTRUMENT
CLUSTER - DIAGNOSIS AND TESTING). For
proper diagnosis of the charging system, the PCI
data bus, or the electronic message inputs to the
instrument cluster that control the charging indica-
tor, 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 is located
KJINSTRUMENT CLUSTER 8J - 15
BRAKE/PARK BRAKE INDICATOR (Continued)
Page 420 of 1803
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 the cluster programming and electronic
messages received by the cluster from the Powertrain
Control Module (PCM) over the Programmable Com-
munications Interface (PCI) data bus. The cruise
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 LED will always be off
when the ignition switch is in any position except On
or Start. The LED only illuminates when it is pro-
vided a path to ground by the instrument cluster
transistor. 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 bulb check por-
tion of the test in order to confirm the functionality
of the LED 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.
DOOR AJAR INDICATOR
DESCRIPTION
A door ajar indicator is standard equipment on all
instrument clusters. The door ajar indicator consists
of the word ªdoorº, which appears in place of the
odometer/trip odometer information in the Vacuum-Fluorescent Display (VFD) of the instrument cluster.
The VFD is part of the cluster electronic circuit
board, and is visible through a cutout located near
the lower edge of the speedometer dial face in the
instrument cluster. The dark outer layer of the over-
lay prevents the VFD from being clearly visible when
it is not illuminated. The word ªdoorº appears in the
same blue-green color and at the same lighting level
as the odometer/trip odometer information through
the translucent outer layer of the overlay when it is
illuminated by the instrument cluster electronic cir-
cuit board. The door ajar indicator is serviced as a
unit with the instrument 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 the instru-
ment cluster electronic 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 door ajar indicator function of
the Vacuum Fluorescent Display (VFD) 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 VFD door ajar indication
will always be off when the ignition switch is in any
position except On or Start. The instrument cluster
will turn on the door ajar indicator for the following
reasons:
²Door Ajar Lamp-On Message- Each time the
cluster receives a door ajar lamp-on message from
the BCM indicating that a door is open or not com-
pletely latched, the door ajar indicator will be illumi-
nated. If the vehicle is not moving when the door
ajar lamp-on message is received, the VFD will
repeatedly and sequentially cycle its indication in
two second intervals with the odometer/trip odometer
information, the door ajar warning, and any other
active warnings including: gate ajar, glass ajar, and
low washer fluid. If the vehicle is moving, or once the
cluster of a non-moving vehicle receives an electronic
vehicle speed message from the Powertrain Control
Module (PCM) indicating a speed greater than zero,
the warning sequence will consist of three complete
display cycles, then revert to only the odometer/trip
odometer display until the door ajar switch is cycled.
The door ajar indicator will also be extinguished
when the cluster receives a door ajar lamp-off mes-
sage from the BCM, or if the ignition switch is
turned to the Off position, whichever occurs first.
KJINSTRUMENT CLUSTER 8J - 17
CRUISE INDICATOR (Continued)
Page 421 of 1803
The BCM continually monitors the door ajar
switches that are integral to each door latch to deter-
mine the status of the doors. The BCM then sends
the proper door ajar lamp-on and lamp-off messages
to the instrument cluster. For further diagnosis of
the door ajar indicator or the instrument cluster cir-
cuitry that controls the indicator, (Refer to 8 - ELEC-
TRICAL/INSTRUMENT CLUSTER - DIAGNOSIS
AND TESTING). For proper diagnosis of the door
ajar switches and circuits, the BCM, the PCI data
bus, or the electronic message inputs to the instru-
ment cluster that control the door ajar indicator, a
DRBIIItscan tool is required. Refer to the appropri-
ate diagnostic information.
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 right
lower corner of the instrument cluster, to the right of
the speedometer. 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 all engines. An International Control and Display
Symbol icon for ªEngine Coolant Temperatureº is
located on the cluster overlay, in the center of the
gauge directly above the hub of the gauge needle.
The engine coolant temperature gauge graphics are
dark blue and black against a beige field, except for a
single light blue graduation at the far left (Cold) end
of the gauge scale and a single red graduation at the
far right (Hot) end of the gauge scale, making them
clearly visible within the instrument cluster in day-
light. When illuminated from behind by the panel
lamps dimmer controlled cluster illumination lighting
with the exterior lamps turned On, the blue graphics
appear blue and the red graphics appear red. The
orange gauge needle is internally illuminated. Gauge
illumination is provided by replaceable incandescent
bulb and bulb holder units located on the instrument
cluster electronic circuit board. The engine coolant
temperature gauge is serviced as a unit with the
instrument cluster.
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 bythe cluster from the Powertrain Control Module
(PCM) over the Programmable Communications
Interface (PCI) data bus. The engine coolant temper-
ature 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 low
end 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:
²Engine Temperature Normal Message- Each
time the cluster receives a message from the PCM
indicating the engine coolant temperature is within
the normal operating range [up to about 124É C (255É
F) for gasoline engines, or about 110É C (230É F) for
diesel engines], the gauge needle is moved to the rel-
ative temperature position of the gauge scale.
²Engine Temperature High Message- Each
time the cluster receives a message from the PCM
indicating the engine coolant temperature is high
[above about 127É C (260É F) for gasoline engines, or
112É C (233É F) for diesel engines], the gauge needle
is moved into the center of the red warning zone on
the gauge scale.
²Engine Temperature Critical Message-
Each time the cluster receives a message from the
PCM indicating the engine coolant temperature is
critical [above about 132É C (269É F) for gasoline
engines, or 115É C (239É F) for diesel engines], the
gauge needle is moved to the high end of the red
warning zone on the gauge scale.
²Actuator Test- Each time the cluster is put
through the actuator test, the gauge needle will be
swept to the gauge calibration points on the gauge
scale in sequence in order to confirm the functional-
ity 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
8J - 18 INSTRUMENT CLUSTERKJ
DOOR AJAR INDICATOR (Continued)
Page 422 of 1803
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 above the
engine temperature gauge and to the right of the
speedometer in the instrument cluster. The front fog
lamp indicator consists of a stencil-like cutout of the
International Control and Display Symbol icon for
ªFront Fog Lightº in the opaque layer of the instru-
ment cluster overlay. The dark outer layer of the
overlay prevents the indicator from being clearly vis-
ible when it is not illuminated. A green Light Emit-
ting Diode (LED) behind the cutout in the opaque
layer of the overlay causes the icon to appear in
green through the translucent outer layer of the
overlay when it is illuminated from behind by the
LED, which is soldered onto 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 control ring on the left con-
trol stalk of the multi-function switch. The front fog
lamp indicator is serviced as a unit with the instru-
ment cluster.
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 electronic circuit
board based upon the 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 front
fog lamp 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 instrument cluster receives a
battery current input on the fused B(+) circuit.
Therefore, the LED can be illuminated regardless of
the ignition switch position. The LED only illumi-
nates 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 fol-
lowing reasons:
²Front Fog Lamp-On Message- Each time the
cluster receives a front fog lamp-on message from the
BCM indicating the front fog lamps are turned On,
the front fog lamp indicator will be illuminated. Theindicator remains illuminated until the cluster
receives a front fog 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, then off again during the bulb
check portion of the test to confirm the functionality
of the LED and the cluster control circuitry.
The BCM continually monitors the exterior light-
ing (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. For
further diagnosis of the front fog lamp indicator or
the instrument cluster circuitry that controls the
indicator, (Refer to 8 - ELECTRICAL/INSTRUMENT
CLUSTER - DIAGNOSIS AND TESTING). For
proper diagnosis of the front fog lamp system, the
BCM, the PCI data bus, or the electronic message
inputs to the instrument cluster that control the
front fog lamp indicator, a DRBIIItscan tool is
required. Refer to the appropriate diagnostic infor-
mation.
FUEL GAUGE
DESCRIPTION
A fuel gauge is standard equipment on all instru-
ment clusters. The fuel gauge is located in the left
lower 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
cluster overlay 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 clus-
ter overlay, in the center of the gauge directly above
the hub of the gauge needle. An arrowhead pointed
to the left side of the vehicle is imprinted on the clus-
ter overlay next to the ªFuelº icon in the fuel gauge
to provide the driver with a reminder as to the loca-
tion of the fuel filler access. The fuel gauge graphics
are dark blue and black against a beige field, except
for a single red graduation at the far left (Empty)
end of the gauge scale, 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 blue graphics appear blue
and the red graphics appear red. The orange gauge
needle is internally illuminated. Gauge illumination
is provided by replaceable incandescent bulb and
bulb holder units located on the instrument cluster
electronic circuit board. The fuel gauge is serviced as
a unit with the instrument cluster.
KJINSTRUMENT CLUSTER 8J - 19
ENGINE TEMPERATURE GAUGE (Continued)
Page 423 of 1803
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 low
end 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.
²Actuator Test- Each time the cluster is put
through the actuator test, the gauge needle will beswept to the gauge calibration points on the gauge
scale in sequence in order to confirm the functional-
ity of the gauge 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. 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.
GATE AJAR INDICATOR
DESCRIPTION
A gate ajar indicator is standard equipment on all
instrument clusters. The gate ajar indicator consists
of the word ªgateº, which appears in place of the
odometer/trip odometer information in the Vacuum-
Fluorescent Display (VFD) of the instrument cluster.
The VFD is part of the cluster electronic circuit
board, and is visible through a cutout located near
the lower edge of the speedometer dial face in the
instrument cluster. The dark outer layer of the over-
lay prevents the VFD from being clearly visible when
it is not illuminated. The word ªgateº appears in the
same blue-green color and at the same lighting level
as the odometer/trip odometer information through
the translucent outer layer of the overlay when it is
illuminated by the instrument cluster electronic cir-
cuit board. The gate ajar indicator is serviced as a
unit with the instrument cluster.
OPERATION
The gate ajar indicator gives an indication to the
vehicle operator that the rear tailgate may be open
or not completely latched. This indicator is controlled
by the instrument cluster electronic 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 gate ajar indica-
tor function of the Vacuum Fluorescent Display
(VFD) 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 VFD
gate ajar indicator will always be off when the igni-
tion switch is in any position except On or Start. The
8J - 20 INSTRUMENT CLUSTERKJ
FUEL GAUGE (Continued)