2002 DODGE RAM Transmission control system

on the instrument cluster circuit board based upon a
hard wired input to the instrument cluster, cluster
programming, and electronic messages received by
the cluster from the Controller Antilock Brake (CAB)
over the Chrysler Collision Detection (CCD) data bus.
The brake indicator Light Emitting Diode (LED)
receives battery current on the instrument cluster
electronic circuit board through the fused ignition
switch output (st-run) circuit whenever the ignition
switch is in the On or Start positions; therefore, the
LED 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 four sec-
onds as a bulb test.
²Park Brake-On- If the park brake is applied
or not fully released with the ignition switch in the
On position, the brake indicator is illuminated solid.
The brake indicator will blink on and off repeatedly
when the park brake is applied or not fully released
and the ignition switch is in the On position if a
vehicle with an automatic transmission is not in
Park or Neutral, or if the engine is running on vehi-
cles with a manual transmission.
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.
²Actuator Test- Each time the instrument clus-
ter is put through the actuator test, the brake indi-
cator will be turned on during the bulb check portion
of the test to confirm the functionality 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 CAB continually
monitors the brake pressure switch on the brake
combination valve to determine if the pressures in
the two halves of the split brake hydraulic system
are unequal. The CAB then 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 itdetects. The park brake switch input to the instru-
ment cluster can be diagnosed using conventional
diagnostic tools and methods. For proper diagnosis of
the antilock brake system, the CAB, the CCD data
bus, or the 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 the brake indicator
comes on or stays on with the ignition switch in the
On position and the park brake released, or comes on
while driving, the brake system must be diagnosed
and repaired prior to performing the following tests.
(Refer to 5 - BRAKES - DIAGNOSIS AND TEST-
ING). If no brake system problem is found, the fol-
lowing procedure will help locate a faulty park brake
switch or park brake switch sense circuit. Refer to
the appropriate wiring information. The wiring infor-
mation 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 con-
nectors, splices and grounds.
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) Disconnect and isolate the battery negative
cable. Disconnect the instrument panel wire harness
connector for the park brake switch from the switch
terminal. With the park brake released, check for
continuity between the park brake switch terminal
and a good ground. There should be no continuity. If
OK, go to Step 2. If not OK, adjust or replace the
faulty park brake switch.
(2) Remove the instrument cluster from the instru-
ment panel. With the park brake switch still discon-
nected, check for continuity between the park brake
switch sense circuit cavity of the instrument panel
wire harness connector for the park brake switch and
a good ground. There should be no continuity. If OK,
go to Step 3. If not OK, repair the shorted park
8J - 16 INSTRUMENT CLUSTERBR/BE
BRAKE/PARK BRAKE INDICATOR (Continued)

instrument cluster housing with two screws. A face
plate on the indicator housing is visible through a
rectangular cutout in the lower right corner of the
instrument cluster overlay, just below the fuel gauge.
Vehicles with a manual transmission have a block-off
plate mounted to the back of the instrument cluster
behind this cutout in the overlay, in place of the gear
selector indicator. Near the top of this face plate the
following characters are imprinted from left to right:
ªP,º ªR,º ªN,º ªD,º ª2,º and ª1.º Respectively, these
characters represent the park, reverse, neutral,
drive, second gear, and first gear positions of the
transmission gear selector lever on the steering col-
umn. Directly below each character on the face plate
is a small, rectangular window, and behind these
windows is a single, movable red pointer.
The gear selector indicator graphics are white
against a black field except for the single red pointer,
making them clearly visible within the instrument
cluster in daylight. When illuminated from behind by
the panel lamps dimmer controlled cluster illumina-
tion lighting with the exterior lamps turned On, the
white graphics appear blue-green, while the red
pointer still appears red. Indicator illumination is
provided by replaceable incandescent bulb and bulb
holder units located on the instrument cluster elec-
tronic circuit board. The gear selector indicator is
available for service replacement separate from the
instrument cluster. The instrument cluster must be
removed from the instrument panel for service access
to the gear selector indicator. (Refer to 8 - ELECTRI-
CAL/INSTRUMENT CLUSTER - REMOVAL).
OPERATION
The mechanical gear selector indicator gives an
indication of the transmission gear that has been
selected with the automatic transmission gear selec-
tor lever. A red pointer appears in a window below
the character in the indicator representing the trans-
mission gear that has been selected. The small,
spring-loaded pointer moves on a track through a
trolley-like mechanism within the indicator housing.
A short length of small diameter stranded cable is
attached to one side of the pointer trolley and is
encased in a tubular plastic housing that exits the
right side of the indicator. The cable is routed
through the instrument panel and under the steering
column to the left side of the column. The looped end
of the cable is hooked over the end of the PRNDL
driver lever on the steering column gearshift mecha-
nism, and the cable housing is secured in a molded
plastic adjuster and bracket on the column housing.
When the gear selector lever is moved the PRNDL
driver lever moves, which moves the pointer through
the mechanical actuator cable. The cable adjuster
and bracket unit mounted on the steering columnhousing provides a mechanical means of calibrating
the gear selector indicator mechanism. (Refer to 19 -
STEERING/COLUMN - INSTALLATION).
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 cluster
overlay, between the tachometer and the speedome-
ter. The high beam indicator consists of a stenciled
cutout of the International Control and Display Sym-
bol icon for ªHigh Beamº 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 blue lens behind
the cutout in the opaque layer of the overlay causes
the icon to appear in blue through the translucent
outer layer of the overlay when it is illuminated from
behind by a replaceable incandescent bulb and bulb
holder unit located on the instrument cluster elec-
tronic circuit board. The high beam indicator is ser-
viced as a unit with the instrument cluster.
OPERATION
The high beam indicator gives an indication to the
vehicle operator when the headlamp high beams are
illuminated. This indicator is hard wired on the
instrument cluster electronic circuit board, and is
controlled by a headlamp beam select switch input to
the cluster. The headlamp high beam indicator bulb
receives battery current on the instrument cluster
electronic circuit board through a fused B(+) circuit
at all times; therefore, the indicator remains opera-
tional regardless of the ignition switch position. The
headlamp beam select switch is integral to the multi-
function switch on the left side of the steering col-
umn, and is connected in series between ground and
the headlamp high beam indicator. The indicator
bulb only illuminates when it is provided with a path
to ground through the high beam indicator driver cir-
cuit by the headlamp beam select switch. (Refer to 8
- ELECTRICAL/LAMPS/LIGHTING - EXTERIOR/
MULTI-FUNCTION SWITCH - OPERATION). The
high beam indicator can be diagnosed using conven-
tional diagnostic tools and methods.
DIAGNOSIS AND TESTING - HIGH BEAM
INDICATOR
The diagnosis found here addresses an inoperative
headlamp high beam indicator condition. If the prob-
lem being diagnosed is related to inoperative head-
lamp high beams, be certain to repair the headlamp
system before attempting to diagnose or repair the
BR/BEINSTRUMENT CLUSTER 8J - 21
GEAR SELECTOR INDICATOR (Continued)

²Engine Oil Pressure Low Message- Each
time the cluster receives a message from the PCM
indicating the engine oil pressure is below about 6.9
kPa (1 psi) for gasoline engines, or 55 kPa (8 psi) for
diesel engines, the gauge needle is moved to the 0
kPa (0 psi) graduation at the far left (low) end of the
gauge scale, the check gauges indicator is illumi-
nated, and a single chime tone is generated. The
gauge needle remains at the low end of the scale and
the check gauges indicator remains illuminated until
the cluster receives a message from the PCM indicat-
ing that the engine oil pressure is above about 6.9
kPa (1 psi) for gasoline engines, or 55 kPa (8 psi) for
diesel engines, or until the ignition switch is turned
to the Off position, whichever occurs first. The clus-
ter will only turn the check gauges indicator lamp on
in response to an engine oil pressure low message if
the engine speed message is greater than zero.
²Engine Oil Pressure High Message- Each
time the cluster receives a message from the PCM
indicating the engine oil pressure is above about 755
kPa (109.5 psi) for gasoline or diesel engines, the
gauge needle is moved to the 758.4 kPa (110 psi)
graduation at the far right (high) end of the gauge
scale. The gauge needle remains at the high end of
the scale until the cluster receives a message from
the PCM indicating that the engine oil pressure is
below about 755 kPa (109.5 psi) for gasoline or diesel
engines, or until the ignition switch is turned to the
Off position, whichever occurs first.
²Message Failure- If the cluster fails to receive
an engine oil pressure message, it will hold the
gauge needle at the last indication until a new mes-
sage is received, 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 gauge needle will be
swept to several calibration points on the gauge scale
in a prescribed sequence in order to confirm the func-
tionality of the gauge and the cluster control cir-
cuitry.
The PCM continually monitors the engine oil pres-
sure sensor to determine the engine oil pressure. The
PCM then sends the proper engine oil pressure mes-
sages to the instrument cluster. For further diagnosis
of the oil pressure gauge or the instrument cluster
circuitry that controls the gauge, (Refer to 8 - ELEC-
TRICAL/INSTRUMENT CLUSTER - DIAGNOSIS
AND TESTING). If the instrument cluster turns on
the check gauges indicator due to a low oil pressure
gauge reading, it may indicate that the engine or the
engine oiling system requires service. For proper
diagnosis of the engine oil pressure sensor, the PCM,
the CCD data bus, or the message inputs to the
instrument cluster that control the oil pressuregauge, a DRBIIItscan tool is required. Refer to the
appropriate diagnostic information.
OVERDRIVE OFF INDICATOR
DESCRIPTION
An overdrive off indicator is standard equipment
on all instrument clusters. However, on vehicles not
equipped with the optional overdrive automatic
transmission, this indicator is electronically disabled.
The overdrive off indicator is located near the lower
edge of the instrument cluster overlay, to the right of
center. The overdrive off indicator consists of a sten-
cilled cutout of the words ªO/D OFFº in the opaque
layer of the instrument cluster overlay. The dark
outer layer of the overlay prevents the indicator from
being clearly visible when it is not illuminated. An
amber lens behind the cutout in the opaque layer of
the overlay causes the ªO/D OFFº text to appear in
amber through the translucent outer layer of the
overlay when the indicator is illuminated from
behind by a Light Emitting Diode (LED) soldered
onto the instrument cluster electronic circuit board.
The overdrive off indicator is serviced as a unit with
the instrument cluster.
OPERATION
The overdrive off indicator gives an indication to
the vehicle operator when the Off position of the
overdrive off switch has been selected, disabling the
electronically controlled overdrive feature of the auto-
matic transmission. This indicator is controlled by a
transistor on the instrument cluster circuit board
based upon the cluster programming and electronic
messages received by the cluster from the Powertrain
Control Module (PCM) over the Chrysler Collision
Detection (CCD) data bus. The overdrive off indicator
Light Emitting Diode (LED) receives battery current
on the instrument cluster electronic circuit board
through the fused ignition switch output (st-run) cir-
cuit whenever the ignition switch is in the On or
Start positions; 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
overdrive off indicator for the following reasons:
²Bulb Test- Each time the ignition switch is
turned to the On position the overdrive off indicator
is illuminated for about two seconds as a bulb test.
²Overdrive Off Lamp-On Message- Each time
the cluster receives an overdrive off lamp-on message
from the PCM indicating that the Off position of the
overdrive off switch has been selected, the overdrive
off indicator will be illuminated. The indicator
8J - 26 INSTRUMENT CLUSTERBR/BE
OIL PRESSURE GAUGE (Continued)

remains illuminated until the cluster receives an
overdrive off 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 indicator will be
turned on 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 overdrive off
switch to determine the proper outputs to the auto-
matic transmission, then sends the proper messages
to the instrument cluster. For further diagnosis of
the overdrive off indicator or the instrument cluster
circuitry that controls the LED, (Refer to 8 - ELEC-
TRICAL/INSTRUMENT CLUSTER - DIAGNOSIS
AND TESTING). For proper diagnosis of the over-
drive control system, the PCM, the CCD data bus, or
the message inputs to the instrument cluster that
control the overdrive off indicator, a DRBIIItscan
tool is required. Refer to the appropriate diagnostic
information.
SEATBELT INDICATOR
DESCRIPTION
A seatbelt indicator is standard equipment on all
instrument clusters. The seatbelt indicator is located
near the lower edge of the instrument cluster overlay,
to the right of center. The seatbelt indicator consists
of a stencilled cutout of the International Control and
Display Symbol icon for ªSeat Beltº 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
lens 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 indi-
cator is illuminated from behind by a Light Emitting
Diode (LED) soldered onto the instrument cluster
electronic circuit board. The seatbelt indicator is ser-
viced as a unit with the instrument cluster.
OPERATION
The seatbelt indicator gives an indication to the
vehicle operator of the status of the driver side front
seatbelt buckle. This indicator is controlled by a tran-
sistor on the instrument cluster circuit board based
upon the cluster programming, and a hard wired
input from the seatbelt switch in the driver side front
seatbelt through the seat belt switch sense circuit.
The seatbelt indicator Light Emitting Diode (LED)
receives battery current on the instrument cluster
electronic circuit board through the fused ignition
switch output (st-run) circuit whenever the ignitionswitch is in the On or Start positions; 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 seatbelt indicator for the following
reasons:
²Seatbelt Reminder Function- Each time the
cluster receives a battery current input on the fused
ignition switch output (st-run) circuit, the indicator
will be illuminated as a seatbelt reminder for about
seven seconds, or until the ignition switch is turned
to the Off position, whichever occurs first. This
reminder function will occur regardless of the status
of the seatbelt switch input to the cluster.
²Driver Side Front Seatbelt Not Buckled-
Following the seatbelt reminder function, each time
the cluster receives a ground input on the seat belt
switch sense circuit (seatbelt switch closed - seatbelt
unbuckled) with the ignition switch in the Start or
On positions, the indicator will be illuminated. The
seatbelt indicator remains illuminated until the seat
belt switch sense input to the cluster is an open cir-
cuit (seatbelt switch opened - seatbelt buckled), 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 indicator will be
turned on during the bulb check portion of the test to
confirm the functionality of the LED and the cluster
control circuitry.
The seatbelt switch input to the instrument cluster
circuitry can be diagnosed using conventional diag-
nostic tools and methods. For further diagnosis of the
seatbelt indicator or the instrument cluster circuitry
that controls the LED, (Refer to 8 - ELECTRICAL/
INSTRUMENT CLUSTER - DIAGNOSIS AND
TESTING).
SERVICE REMINDER
INDICATOR
DESCRIPTION
A Service Reminder Indicator (SRI) is standard
equipment on all instrument clusters. However, on
vehicles not equipped with certain optional heavy
duty emission cycle gasoline engines, this indicator is
electronically disabled. The SRI is located near the
lower edge of the instrument cluster overlay, to the
left of center. The SRI consists of a stencilled cutout
of the words ªMAINT REQDº in the opaque layer of
the instrument cluster overlay. The dark outer layer
of the overlay prevents the indicator from being
clearly visible when it is not illuminated. An amber
lens behind the cutout in the opaque layer of the
BR/BEINSTRUMENT CLUSTER 8J - 27
OVERDRIVE OFF INDICATOR (Continued)

sage is not received after about four seconds, the
gauge needle will return to the far left (low) end of
the scale.
²Actuator Test- Each time the cluster is put
through the actuator test, the gauge needle will be
swept to several calibration points on the gauge scale
in a prescribed sequence in order to confirm the func-
tionality of the gauge and the cluster control cir-
cuitry.
The PCM continually monitors the crankshaft posi-
tion sensor to determine the engine speed, then
sends the proper engine speed messages to the
instrument cluster. For further diagnosis of the
tachometer or the instrument cluster circuitry that
controls the gauge, (Refer to 8 - ELECTRICAL/IN-
STRUMENT CLUSTER - DIAGNOSIS AND TEST-
ING). For proper diagnosis of the crankshaft position
sensor, the PCM, the CCD data bus, or the message
inputs to the instrument cluster that control the
tachometer, a DRBIIItscan tool is required. Refer to
the appropriate diagnostic information.
TRANS OVERTEMP
INDICATOR
DESCRIPTION
A transmission over-temperature indicator lamp is
standard equipment on all instrument clusters. How-
ever, on vehicles not equipped with the optional auto-
matic transmission, this indicator is electronically
disabled. The transmission over-temperature indica-
tor is located near the lower edge of the instrument
cluster overlay, to the left of center. The transmission
over-temperature indicator consists of a stencilled
cutout of the words ªTRANS TEMPº 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
lens behind the cutout in the opaque layer of the
overlay causes the ªTRANS TEMPº text to appear in
red through the translucent outer layer of the over-
lay when the indicator is illuminated from behind by
a Light Emitting Diode (LED) soldered onto the
instrument cluster electronic circuit board. The
transmission over-temperature indicator is serviced
as a unit with the instrument cluster.
OPERATION
The transmission over-temperature indicator gives
an indication to the vehicle operator when the trans-
mission fluid temperature is excessive, which may
lead to accelerated transmission component wear or
failure. This indicator is controlled by a transistor on
the instrument cluster circuit board based upon the
cluster programming and electronic messagesreceived by the cluster from the Powertrain Control
Module (PCM) over the Chrysler Collision Detection
(CCD) data bus. The transmission over-temperature
indicator Light Emitting Diode (LED) receives bat-
tery current on the instrument cluster electronic cir-
cuit board through the fused ignition switch output
(st-run) circuit whenever the ignition switch is in the
On or Start positions; 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 transmission over-temperature indicator for
the following reasons:
²Bulb Test- Each time the ignition switch is
turned to the On position the transmission over-tem-
perature indicator is illuminated for about two sec-
onds as a bulb test.
²Trans Over-Temp Lamp-On Message- Each
time the cluster receives a trans over-temp lamp-on
message from the PCM indicating that the transmis-
sion fluid temperature is 135É C (275É F) or higher,
the indicator will be illuminated and a single chime
tone is sounded. The lamp remains illuminated until
the cluster receives a trans over-temp lamp-off mes-
sage from the PCM, or until the ignition switch is
turned to the Off position, whichever occurs first.
The chime tone feature will only repeat during the
same ignition cycle if the transmission over-tempera-
ture indicator is cycled off and then on again by the
appropriate trans over-temp messages from the PCM.
²Actuator Test- Each time the cluster is put
through the actuator test, the indicator will be
turned on 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 transmission
temperature sensor to determine the transmission
operating condition, then sends the proper messages
to the instrument cluster. If the instrument cluster
turns on the transmission over-temperature indicator
due to a high transmission oil temperature condition,
it may indicate that the transmission and/or the
transmission cooling system are being overloaded or
that they require service. For further diagnosis of the
transmission over-temperature indicator or the
instrument cluster circuitry that controls the LED,
(Refer to 8 - ELECTRICAL/INSTRUMENT CLUS-
TER - DIAGNOSIS AND TESTING). For proper
diagnosis of the transmission temperature sensor, the
PCM, the CCD data bus, or the message inputs to
the instrument cluster that control the transmission
over-temperature indicator, a DRBIIItscan tool is
required. Refer to the appropriate diagnostic infor-
mation.
BR/BEINSTRUMENT CLUSTER 8J - 31
TACHOMETER (Continued)

TURN SIGNAL INDICATOR
DESCRIPTION
Two turn signal indicators are standard equipment
on all instrument clusters. The turn signal indicators
are located near the upper edge of the instrument
cluster overlay, between the speedometer and the
tachometer. Each turn signal indicator consists of a
stenciled cutout of the International Control and Dis-
play Symbol icon for ªTurn Warningº in the opaque
layer of the instrument cluster overlay. The dark
outer layer of the overlay prevents these icons from
being clearly visible when their lamps are not illumi-
nated. The icons appear in green 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 turn signal
indicators are serviced as a unit with the instrument
cluster.
OPERATION
The turn signal indicators give an indication to the
vehicle operator that the turn signal (left or right
indicator flashing) or hazard warning (both left and
right indicators flashing) have been selected. These
indicators are controlled by two individual hard
wired inputs to the instrument cluster electronic cir-
cuit board. The turn signal indicator bulbs are
grounded on the instrument cluster electronic circuit
board at all times. The turn signal indicator bulbs
only illuminate when they are provided with battery
current by the turn signal and hazard warning
switch circuitry of the left multi-function switch on
the steering column through separate left and right
turn signal inputs to the instrument cluster; there-
fore, these indicators can be illuminated, regardless
of the ignition switch position.
The turn signal indicators are connected in series
between ground and the output of the turn signal
and hazard warning switch circuitry, but in parallel
with the other turn signal circuits. This arrangement
allows the turn signal indicators to remain functional
regardless of the condition of the other circuits in the
turn signal and hazard warning system. For more
information on the turn signal and hazard warning
system, (Refer to 8 - ELECTRICAL/LAMPS/LIGHT-
ING - EXTERIOR - OPERATION - TURN SIGNAL &
HAZARD WARNING SYSTEM). The turn signal
indicators can be diagnosed using conventional diag-
nostic tools and methods.
DIAGNOSIS AND TESTING - TURN SIGNAL
INDICATOR
The diagnosis found here addresses an inoperative
turn signal indicator lamp condition. If the problem
being diagnosed is related to inoperative turn signals
or hazard warning lamps, be certain to repair the
turn signal and hazard warning system before
attempting to diagnose or repair the turn signal indi-
cators. If no turn signal or hazard warning system
problems are found, the following procedure will help
locate a short or open in the left or right turn signal
indicator circuit. Refer to the appropriate wiring
information. The wiring information includes wiring
diagrams, proper wire and connector repair proce-
dures, details of wire harness routing and retention,
connector pin-out information and location views for
the various wire harness connectors, splices and
grounds.
(1) Disconnect and isolate the battery negative
cable. Remove the instrument cluster.
(2) Connect the battery negative cable. Activate
the hazard warning system by moving the hazard
warning switch button to the On position. Check for
battery voltage at the inoperative (right or left) turn
signal circuit cavity of the instrument panel wire
harness connector (Connector C2) for the instrument
cluster. There should be a switching (on and off) bat-
tery voltage signal. If OK, replace the faulty turn sig-
nal indicator bulb. If not OK, repair the open (right
or left) turn signal circuit to the left multi-function
switch as required.
UPSHIFT INDICATOR
DESCRIPTION
An upshift indicator is standard equipment on all
instrument clusters. However, on vehicles not
equipped with a manual transmission, this indicator
is disabled. The upshift indicator is located near the
fuel gauge in the instrument cluster overlay, to the
left of center. The upshift indicator consists of an
upward pointed arrow icon that is a stenciled cutout
in the opaque layer of the instrument cluster overlay.
The dark outer layer of the overlay prevents the indi-
cator from being clearly visible when it is not illumi-
nated. An amber lens behind the cutout in the
opaque layer of the overlay causes the icon to appear
in amber through the translucent outer layer of the
overlay when the indicator is illuminated from
behind by a replaceable incandescent bulb and bulb
holder unit located on the instrument cluster elec-
tronic circuit board. The upshift indicator is serviced
as a unit with the instrument cluster.
8J - 32 INSTRUMENT CLUSTERBR/BE

OPERATION
The upshift indicator gives an indication to the
vehicle operator when the transmission should be
shifted to the next highest gear in order to achieve
the best fuel economy. This indicator is controlled by
a transistor on the instrument cluster circuit board
based upon the cluster programming and electronic
messages received by the cluster from the Powertrain
Control Module (PCM) over the Chrysler Collision
Detection (CCD) data bus. The upshift indicator bulb
receives battery current on the instrument cluster
electronic circuit board through the fused ignition
switch output (st-run) circuit whenever the ignition
switch is in the On or Start positions; therefore, the
lamp will always be off when the ignition switch is in
any position except On or Start. The bulb only illu-
minates when it is provided a path to ground by the
instrument cluster transistor. On models not
equipped with a manual transmission, the incandes-
cent bulb and bulb holder unit are not installed at
the factory when the vehicle is built. The instrument
cluster will turn on the upshift indicator for the fol-
lowing reasons:
²Upshift Lamp-On Message- Each time the
cluster receives an upshift lamp-on message from the
PCM indicating the engine speed and load conditions
are right for a transmission upshift to occur, the
upshift indicator is illuminated. The indicator
remains illuminated until the cluster receives an
upshift lamp-off message from the PCM or until the
ignition switch is turned to the Off position, which-
ever occurs first. The PCM will normally send an
upshift lamp-off message three to five seconds after a
lamp-on message, if an upshift is not performed. The
indicator will then remain off until the vehicle stops
accelerating and is brought back into the range of
indicator operation, or until the transmission is
shifted into another gear.
²Actuator Test- Each time the cluster is put
through the actuator test, the indicator will be
turned on during the bulb check portion of the test to
confirm the functionality of the indicator and the
cluster control circuitry.
The PCM continually monitors the engine speed
and load conditions to determine the proper fuel and
ignition requirements. The PCM then sends the
proper messages to the instrument cluster. If the
upshift indicator fails to light during normal vehicle
operation, replace the bulb with a known good unit.
For further diagnosis of the upshift 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 PCM, the CCD data bus, or
the message inputs to the instrument cluster that
control the upshift indicator, a DRBIIItscan tool isrequired. Refer to the appropriate diagnostic infor-
mation.
VOLTAGE GAUGE
DESCRIPTION
A voltage gauge is standard equipment on all
instrument clusters. The voltage gauge is located in
the upper left quadrant of the instrument cluster,
above the temperature gauge. The voltage gauge con-
sists 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 8 volts to 18 volts. An International Con-
trol and Display Symbol icon for ªBattery Charging
Conditionº is located directly below the lowest grad-
uation of the gauge scale. The voltage gauge graphics
are white against a black field except for a single red
graduation at each end of the gauge scale, making
them clearly visible within the instrument cluster in
daylight. When illuminated from behind by the panel
lamps dimmer controlled cluster illumination lighting
with the exterior lamps turned On, the white graph-
ics appear blue-green and the red graphics appear
red. The orange gauge needle is internally illumi-
nated. Gauge illumination is provided by replaceable
incandescent bulb and bulb holder units located on
the instrument cluster electronic circuit board. The
voltage gauge is serviced as a unit with the instru-
ment cluster.
OPERATION
The voltage gauge gives an indication to the vehi-
cle operator of the electrical system voltage. This
gauge is controlled by the instrument cluster circuit
board based upon the cluster programming and elec-
tronic messages received by the cluster from the
Powertrain Control Module (PCM) over the Chrysler
Collision Detection (CCD) data bus. The voltage
gauge is an air core magnetic unit that receives bat-
tery current on the instrument cluster electronic cir-
cuit board through the fused ignition switch output
(st-run) circuit whenever the ignition switch is in the
On or Start positions. The cluster is programmed 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:
²Charge Fail Message- Each time the cluster
receives a message from the PCM indicating a charge
fail condition (system voltage is 10.8 volts or lower),
the gauge needle is moved to the 8 volt graduation
on the gauge scale and the check gauges indicator is
illuminated. The gauge needle remains on the 8 volt
BR/BEINSTRUMENT CLUSTER 8J - 33
UPSHIFT INDICATOR (Continued)

²Airbag Control Module- The Airbag Control
Module (ACM) is located in a stamped mounting
bracket on the floor panel transmission tunnel, below
the center of the instrument panel.
²Airbag Indicator- The airbag indicator is inte-
gral to the ElectroMechanical Instrument Cluster
(EMIC), which is located on the instrument panel in
front of the driver.
²Clockspring- The clockspring is located near
the top of the steering column, directly beneath the
steering wheel.
²Driver Airbag- The driver airbag is located in
the center of the steering wheel, beneath the driver
airbag trim cover.
²Driver Knee Blocker- The driver knee blocker
is a molded plastic structural unit secured to the
back side of and integral to the instrument panel
steering column opening cover.
²Passenger Airbag- The passenger airbag is
located on the instrument panel, beneath the passen-
ger airbag door on the instrument panel above the
glove box on the passenger side of the vehicle.
²Passenger Airbag On/Off Switch- The pas-
senger airbag on/off switch is located in a dedicated
opening in the upper right corner of the instrument
panel cluster bezel, to the right of the center panel
outlets of the climate control system.
²Passenger Knee Blocker- The passenger knee
blocker is a structural reinforcement that is integral
to and concealed within the glove box door.
The ACM and the EMIC each contain a central
processing unit and programming that allow them to
communicate with each other using the Chrysler Col-
lision Detection (CCD) data bus network. This
method of communication is used for control of the
airbag indicator on all models. (Refer to 8 - ELEC-
TRICAL/ELECTRONIC CONTROL MODULES/
COMMUNICATION - DESCRIPTION).Hard wired circuitry connects the airbag system
components to each other through the electrical sys-
tem of the vehicle. These hard wired circuits are
integral to several wire harnesses, which are routed
throughout the vehicle and retained by many differ-
ent methods. These circuits may be connected to each
other, to the vehicle electrical system, and to the air-
bag system components through the use of a combi-
nation of soldered splices, splice block connectors,
and many different types of wire harness terminal
connectors and insulators. Refer to the appropriate
wiring information. The wiring information includes
wiring diagrams, proper wire and connector repair
procedures, further details on wire harness routing
and retention, as well as pin-out and location views
for the various wire harness connectors, splices and
grounds.OPERATION
The airbag system is referred to as a supplemental
restraint system because it was designed and is
intended to enhance the protection for the front seat
occupants of the vehicleonlywhen used in conjunc-
tion with the seat belts. It is referred to as a passive
system because the vehicle occupants are not
required to do anything to make it work. The pri-
mary passenger restraints in this or any other vehi-
cle are the standard equipment factory-installed seat
belts. Seat belts are referred to as an active restraint
because the vehicle occupants are required to physi-
cally fasten and properly adjust these restraints in
order to benefit from them. The vehicle occupants
must be wearing their seat belts in order to obtain
the maximum safety benefit from the factory-in-
stalled airbag system.
The airbag system electrical circuits are continu-
ously monitored and controlled by a microprocessor
and software contained within the Airbag Control
Module (ACM). An airbag indicator in the ElectroMe-
chanical Instrument Cluster (EMIC) lights for about
seven seconds as a bulb test each time the ignition
switch is turned to the On or Start positions. Follow-
ing the bulb test, the airbag indicator is turned on or
off by the ACM to indicate the status of the airbag
system. If the airbag indicator comes on at any time
other than during the bulb test, it indicates that
there is a problem in the airbag system electrical cir-
cuits. Such a problem may cause the airbags not to
deploy when required, or to deploy when not
required.
The clockspring on the top of the steering column
allows a continuous electrical circuit to be main-
tained between the stationary steering column and
the driver airbag inflator, which rotates with the
steering wheel. The passenger airbag on/off switch
allows the passenger side airbag to be disabled when
Fig. 1 SRS Logo
8O - 2 RESTRAINTSBR/BE
RESTRAINTS (Continued)