2001 DODGE RAM Control vacuum

(10) Lift radiator straight up and out of engine
compartment. The bottom of the radiator is equipped
with two alignment dowels that fit into holes in the
lower radiator support panel (Fig. 42). Rubber bis-
cuits (insulators) are installed to these dowels. Take
care not to damage cooling fins or tubes on the radi-
ator and air conditioning condenser when removing.
CLEANING
Clean radiator fins are necessary for good heat
transfer. The radiator and air conditioning fins
should be cleaned when an accumulation of debris
has occurred. With the engine cold, apply cold water
and compressed air to the back (engine side) of the
radiator to flush the radiator and/or A/C condenser of
debris.
INSPECTION
Inspect the radiator side tanks for cracks, broken
or missing fittings also inspect the joint where the
tanks seam up to the radiator core for signs of leak-
age and/or deteriorating seals.
Inspect radiator core for corroded, bent or missing
cooling fins. Inspect the core for bent or damaged
cooling tubes.
INSTALLATION
(1) Position fan shroud over the fan blades rear-
ward towards engine.
(2) Install rubber insulators to alignment dowels
at lower part of radiator.
(3) Lower the radiator into position while guiding
the two alignment dowels into lower radiator sup-
port. Different alignment holes are provided in the
lower radiator support for each engine application.
(4) Install two upper radiator mounting bolts.
Tighten bolts to 11 N´m (95 in. lbs.) torque.
(5) Connect both radiator hoses and install hose
clamps.
(6) Connect transmission cooler lines to radiator
tank. Inspect quick connect fittings for debris and
install until an audible ªclickº is heard. Pull apart to
verify connection.
(7) Install windshield washer reservoir tank.
(8) Position fan shroud to flanges on sides of radi-
ator. Install fan shroud mounting bolts (Fig. 41).
Tighten bolts to 6 N´m (50 in. lbs.) torque.
(9) Install metal clips to top of fan shroud.
(10) Install coolant reserve/overflow tank hose to
radiator filler neck nipple.
(11) Install coolant reserve/overflow tank to fan
shroud (fits into T-slots on shroud).
(12) Install battery negative cables.
(13) Install positive battery cable to top of radia-
tor. Tighten radiator-to-battery cable mounting nuts.
(14) Position heater controls tofull heatposition.(15) Fill cooling system with coolant (Refer to 7 -
COOLING - STANDARD PROCEDURE).
(16) Operate engine until it reaches normal tem-
perature. Check cooling system and automatic trans-
mission (if equipped) fluid levels.
RADIATOR PRESSURE CAP
DESCRIPTION
Radiators are equipped with a pressure cap, which
releases pressure at some point within a range of
97-124 kPa (14-18 psi). The pressure relief point (in
pounds) is engraved on top of cap.
The cooling system will operate at pressures
slightly above atmospheric pressure. This results in a
higher coolant boiling point allowing increased radi-
ator cooling capacity.
A rubber gasket seals radiator filler neck to pre-
vent leakage. This is done to keep system under
pressure. It also maintains vacuum during coolant
cool-down allowing coolant to return from reserve/
overflow tank.
OPERATION
The cap (Fig. 43) contains a spring-loaded pressure
relief valve that opens when system pressure reaches
release range of 97-124 kPa (14-18 psi).
A vent valve in the center of cap allows a small
coolant flow through cap when coolant is below boil-
ing temperature. The valve is completely closed when
boiling point is reached. As the coolant cools, it con-
Fig. 43 Radiator Pressure Cap and Filler NeckÐ
Typical
1 - STAINLESS-STEEL SWIVEL TOP
2 - RUBBER SEALS
3 - VENT VALVE
4 - RADIATOR TANK
5 - FILLER NECK
6 - OVERFLOW NIPPLE
7 - MAIN SPRING
8 - GASKET RETAINER
BR/BEENGINE 7 - 65
RADIATOR - 5.9L DIESEL (Continued)

Based on inputs that it receives, the PCM adjusts
ignition coil dwell. The PCM also adjusts the gener-
ator charge rate through control of the generator
field and provides speed control operation.
NOTE: PCM Inputs:
²A/C request (if equipped with factory A/C)
²A/C select (if equipped with factory A/C)
²Auto shutdown (ASD) sense
²Battery temperature
²Battery voltage
²Brake switch
²CCD bus (+) circuits
²CCD bus (-) circuits
²Camshaft position sensor signal
²Crankshaft position sensor
²Data link connection for DRB scan tool
²Engine coolant temperature sensor
²Fuel level
²Generator (battery voltage) output
²Ignition circuit sense (ignition switch in on/off/
crank/run position)
²Intake manifold air temperature sensor
²Leak detection pump (switch) sense (if equipped)
²Manifold absolute pressure (MAP) sensor
²Oil pressure
²Output shaft speed sensor
²Overdrive/override switch
²Oxygen sensors
²Park/neutral switch (auto. trans. only)
²Power ground
²Sensor return
²Signal ground
²Speed control multiplexed single wire input
²Throttle position sensor
²Transmission governor pressure sensor
²Transmission temperature sensor
²Vehicle speed inputs from ABS or RWAL system
NOTE: PCM Outputs:
²A/C clutch relay
²Auto shutdown (ASD) relay
²CCD bus (+/-) circuits for: speedometer, voltme-
ter, fuel gauge, oil pressure gauge/lamp, engine temp.
gauge and speed control warn. lamp
²Data link connection for DRB scan tool
²EGR valve control solenoid (if equipped)
²EVAP canister purge solenoid
²Five volt sensor supply (primary)
²Five volt sensor supply (secondary)
²Fuel injectors
²Fuel pump relay
²Generator field driver (-)
²Generator field driver (+)
²Generator lamp (if equipped)²Idle air control (IAC) motor
²Ignition coil
²Leak detection pump (if equipped)
²Malfunction indicator lamp (Check engine lamp).
Driven through CCD circuits.
²Overdrive indicator lamp (if equipped)
²Service Reminder Indicator (SRI) Lamp (MAINT
REQ'D lamp). Driven through CCD circuits.
²Speed control vacuum solenoid
²Speed control vent solenoid
²Tachometer (if equipped). Driven through CCD
circuits.
²Transmission convertor clutch circuit
²Transmission 3±4 shift solenoid
²Transmission relay
²Transmission temperature lamp (if equipped)
²Transmission variable force solenoid
OPERATION - DIESEL
Two different control modules are used: The Pow-
ertrain Control Module (PCM), and the Engine Con-
trol Module (ECM). The ECMcontrolsthe fuel
system. The PCMdoes not controlthe fuel system.
The PCM's main function is to control: the vehicle
charging system, speed control system, transmission,
air conditioning system and certain bussed messages.
The PCM can adapt its programming to meet
changing operating conditions.
The PCM receives input signals from various
switches and sensors. Based on these inputs, the
PCM regulates various engine and vehicle operations
through different system components. These compo-
nents are referred to asPCM Outputs.The sensors
and switches that provide inputs to the PCM are con-
sideredPCM Inputs.
NOTE: PCM Inputs:
²A/C request (if equipped with factory A/C)
²A/C select (if equipped with factory A/C)
²Accelerator Pedal Position Sensor (APPS) output
from ECM
²Auto shutdown (ASD) relay sense
²Battery temperature sensor
²Battery voltage
²Brake switch
²CCD bus (+) circuits
²CCD bus (-) circuits
²Crankshaft Position Sensor (CKP) output from
ECM
²Data link connection for DRB scan tool
²Fuel level sensor
²Generator (battery voltage) output
²Ignition sense
²Output shaft speed sensor
²Overdrive/override switch
²Park/neutral switch (auto. trans. only)
8E - 18 ELECTRONIC CONTROL MODULESBR/BE
POWERTRAIN CONTROL MODULE (Continued)

²Power ground
²Sensor return
²Signal ground
²Speed control resume switch
²Speed control set switch
²Speed control on/off switch
²Transmission governor pressure sensor
²Transmission temperature sensor
²Vehicle speed inputs from ABS or RWAL system
NOTE: PCM Outputs:
After inputs are received by the PCM, certain sen-
sors, switches and components are controlled or reg-
ulated by the PCM. These are consideredPCM
Outputs.These outputs are for:
²A/C clutch relay and A/C clutch
²Auto shutdown (ASD) relay
²CCD bus (+/-) circuits for: speedometer, voltme-
ter, fuel gauge, oil pressure gauge/lamp, engine temp.
gauge and speed control warn. lamp
²Data link connection for DRB scan tool
²Five volt sensor supply
²Generator field driver (-)
²Generator field driver (+)
²Generator lamp (if equipped)
²Malfunction indicator lamp (Check engine lamp)
²Overdrive warning lamp (if equipped)
²Speed control vacuum solenoid
²Speed control vent solenoid
²Tachometer (if equipped)
²Transmission convertor clutch circuit
²Transmission 3±4 shift solenoid
²Transmission relay
²Transmission temperature lamp (if equipped)
²Transmission variable force solenoid (governor
sol.)
OPERATION - 5 VOLT SUPPLIES
Primary 5±volt supply:
²supplies the required 5 volt power source to the
Crankshaft Position (CKP) sensor.
²supplies the required 5 volt power source to the
Camshaft Position (CMP) sensor.
²supplies a reference voltage for the Manifold
Absolute Pressure (MAP) sensor.
²supplies a reference voltage for the Throttle
Position Sensor (TPS) sensor.
Secondary 5±volt supply:
²supplies the required 5 volt power source to the
oil pressure sensor.
²supplies the required 5 volt power source for the
Vehicle Speed Sensor (VSS) (if equipped).
²supplies the 5 volt power source to the transmis-
sion pressure sensor (if equipped with an RE auto-
matic transmission).
OPERATION - IGNITION CIRCUIT SENSE
The ignition circuit sense input tells the PCM the
ignition switch has energized the ignition circuit.
Battery voltage is also supplied to the PCM
through the ignition switch when the ignition is in
the RUN or START position. This is referred to as
the9ignition sense9circuit and is used to9wake up9
the PCM. Voltage on the ignition input can be as low
as 6 volts and the PCM will still function. Voltage is
supplied to this circuit to power the PCM's 8-volt reg-
ulator and to allow the PCM to perform fuel, ignition
and emissions control functions.
REMOVAL
USE THE DRB SCAN TOOL TO REPROGRAM
THE NEW POWERTRAIN CONTROL MODULE
(PCM) WITH THE VEHICLES ORIGINAL IDEN-
TIFICATION NUMBER (VIN) AND THE VEHI-
CLES ORIGINAL MILEAGE. IF THIS STEP IS
NOT DONE, A DIAGNOSTIC TROUBLE CODE
(DTC) MAY BE SET.
The PCM is located in the engine compartment
(Fig. 18).
To avoid possible voltage spike damage to the
PCM, ignition key must be off, and negative battery
cable must be disconnected before unplugging PCM
connectors.
(1) Disconnect negative battery cable(s) at bat-
tery(s).
(2) Remove cover over electrical connectors. Cover
snaps onto PCM.
(3) Carefully unplug the three 32±way connectors
from PCM.
Fig. 18 PCM Location and Mounting
1 - PCM MOUNTING BOLTS (3)
2 - POWERTRAIN CONTROL MODULE (PCM)
3 - (3) 32±WAY CONNECTORS
BR/BEELECTRONIC CONTROL MODULES 8E - 19
POWERTRAIN CONTROL MODULE (Continued)

OPERATION
The camshaft position sensor provides fuel injec-
tion synchronization and cylinder identification.
The distributor does not have built in centrifugal
or vacuum assisted advance. Base ignition timing
and all timing advance is controlled by the Power-
train Control Module (PCM). Because ignition timing
is controlled by the PCM,base ignition timing is
not adjustable.
The distributor is held to the engine in the conven-
tional method using a holddown clamp and bolt.
Although the distributor can be rotated, it will
have no effect on ignition timing.
All distributors contain an internal oil seal that
prevents oil from entering the distributor housing.
The seal is not serviceable.
REMOVAL
CAUTION: Base ignition timing is not adjustable on
any engine. Distributors do not have built in centrif-
ugal or vacuum assisted advance. Base ignition
timing and timing advance are controlled by the
Powertrain Control Module (PCM). Because a con-
ventional timing light can not be used to adjust dis-
tributor position after installation, note position of
distributor before removal.
(1) Remove air cleaner assembly.
(2) Disconnect negative cable from battery.
(3) Remove distributor cap from distributor (two
screws).
(4) Mark the position of distributor housing in
relationship to engine or dash panel. This is done to
aid in installation.(5) Before distributor is removed, the number one
cylinder must be brought to the Top Dead Center
(TDC) firing position.
(6) Attach a socket to the Crankshaft Vibration
Damper mounting bolt.
(7) Slowly rotate engine clockwise, as viewed from
front, until indicating mark on crankshaft vibration
damper is aligned to 0 degree (TDC) mark on timing
chain cover (Fig. 18).
(8) The distributor rotor should now be aligned to
the CYL. NO. 1 alignment mark (stamped) into the
camshaft position sensor (Fig. 19). If not, rotate the
crankshaft through another complete 360 degree
turn. Note the position of the number one cylinder
spark plug cable (on the cap) in relation to rotor.
Rotor should now be aligned to this position.
(9) Disconnect camshaft position sensor wiring
harness from main engine wiring harness.
(10) Remove distributor rotor from distributor
shaft.
(11) Remove distributor holddown clamp bolt and
clamp (Fig. 20). Remove distributor from vehicle.
CAUTION: Do not crank engine with distributor
removed. Distributor/crankshaft relationship will be
lost.
INSTALLATION
If engine has been cranked while distributor is
removed, establish the relationship between distribu-
tor shaft and number one piston position as follows:
Rotate crankshaft in a clockwise direction, as
viewed from front, until number one cylinder piston
is at top of compression stroke (compression should
be felt on finger with number one spark plug
Fig. 17 Distributor and Camshaft Position Sensor
1 - SYNC SIGNAL GENERATOR
2 - CAMSHAFT POSITION SENSOR
3 - PULSE RING
4 - DISTRIBUTOR ASSEMBLY
Fig. 18 Damper-To-Cover Alignment MarksÐTypical
1 - ALIGNMENT MARK
2 - TIMING CHAIN COVER MARKS
3 - CRANKSHAFT VIBRATION DAMPER
BR/BEIGNITION CONTROL 8I - 11
DISTRIBUTOR (Continued)

INSTRUMENT CLUSTER
DESCRIPTION
The instrument cluster for this model is an Elec-
troMechanical Instrument Cluster (EMIC) module
that is located in the instrument panel above the
steering column opening, directly in front of the
driver (Fig. 1). The EMIC gauges and indicators are
protected by an integral clear plastic cluster lens,
and are visible through a dedicated opening in the
cluster bezel on the instrument panel. Just behind
the cluster lens is the cluster hood. The cluster hood
serves as a visor and shields the face of the cluster
from ambient light and reflections to reduce glare.
Behind the cluster hood is the cluster overlay and
gauges. The overlay is a multi-layered unit. The
dark, visible surface of the outer layer of the overlay
is marked with all of the gauge identification and
graduations, but this layer is also translucent. The
darkness of this outer layer prevents the cluster from
appearing cluttered or busy by concealing the cluster
indicators that are not illuminated, while the trans-
lucence of this layer allows those indicators and icons
that are illuminated to be readily visible. The under-
lying layer of the overlay is opaque and allows light
from the various indicators and illumination lamps
behind it to be visible through the outer layer of the
overlay only through predetermined cutouts. On the
lower edge of the cluster lens just left of center, the
odometer/trip odometer switch knob protrudesthrough a dedicated hole in the lens. The remainder
of the EMIC, including the mounts and the electrical
connections, are concealed behind the cluster bezel.
The molded plastic EMIC housing has four integral
mounting tabs, two each on the upper and lower
edges of the housing. The EMIC is secured to the
molded plastic instrument panel cluster carrier with
four screws. All electrical connections to the EMIC
are made at the back of the cluster housing through
two take outs of the instrument panel wire harness,
each equipped with a self-docking connector.
A single EMIC module is offered on this model.
This module utilizes integrated circuitry and infor-
mation carried on the Chrysler Collision Detection
(CCD) data bus network for control of all gauges and
many of the indicators. (Refer to 8 - ELECTRICAL/
ELECTRONIC CONTROL MODULES/COMMUNI-
CATION - DESCRIPTION). The EMIC also uses
several hard wired inputs in order to perform its
many functions. In addition to instrumentation and
indicators, the EMIC has hardware and/or software
to support the following functions:
²Chime Warning Requests- The EMIC sends
chime tone requests over a hard wired circuit to the
Central Timer Module (CTM) when it monitors cer-
tain conditions or inputs. The CTM replaces the
chime or buzzer module and performs the functions
necessary to provide audible alerts that are synchro-
nized with the visual alerts provided by the EMIC.
(Refer to 8 - ELECTRICAL/CHIME/BUZZER -
DESCRIPTION).
²Vacuum Fluorescent Display (VFD) Dim-
ming Service- The EMIC performs the functions
necessary to eliminate the need for a separate VFD
dimming module by providing control and synchroni-
zation of the illumination intensity of all vacuum flu-
orescent displays in the vehicle, as well as a parade
mode.
The EMIC module incorporates a blue-green digital
VFD for displaying odometer and trip odometer infor-
mation, as well as the amber cruise-on indicator dis-
play function. Some variations of the EMIC are
necessary to support optional equipment and regula-
tory requirements. The EMIC includes the following
analog gauges:
²Coolant Temperature Gauge
²Fuel Gauge
²Oil Pressure Gauge
²Speedometer
²Tachometer
²Voltage Gauge
The EMIC also includes provisions for the follow-
ing indicators:
²Airbag Indicator
²Antilock Brake System (ABS) Indicator
²Brake Indicator
Fig. 1 Instrument Cluster Components
1 - COVER
2 - HOUSING
3 - OVERLAY AND GAUGES
4 - HOOD
5 - LENS
6 - CIRCUIT BOARD
7 - ODOMETER SWITCH BUTTON
8J - 2 INSTRUMENT CLUSTERBR/BE

The EMIC circuitry operates on battery current
received through a fused B(+) fuse in the Junction
Block (JB) on a non-switched fused B(+) circuit, and
on battery current received through a fused ignition
switch output (st-run) fuse in the JB on a fused igni-
tion switch output (st-run) circuit. This arrangement
allows the EMIC to provide some features regardless
of the ignition switch position, while other features
will operate only with the ignition switch in the Start
or On positions. The EMIC circuitry is grounded
through two separate ground circuits located in one
of the two instrument cluster connectors and take
outs of the instrument panel wire harness. One
ground circuit receives ground through a take out
with an eyelet terminal connector of the instrument
panel wire harness that is secured by a nut to a
ground stud located on the left instrument panel end
bracket, while the other ground circuit receives
ground through a take out with an eyelet terminal
connector of the instrument panel wire harness that
is secured by a nut to a ground stud located on the
back of the instrument panel armature above the
inboard side of the instrument panel steering column
opening.
The EMIC also has a self-diagnostic actuator test
capability, which will test each of the CCD bus mes-
sage-controlled functions of the cluster by lighting
the appropriate indicators and positioning the gauge
needles at several predetermined locations on the
gauge faces in a prescribed sequence. (Refer to 8 -
ELECTRICAL/INSTRUMENT CLUSTER - DIAGNO-
SIS AND TESTING). See the owner's manual in the
vehicle glove box for more information on the fea-
tures, use and operation of the EMIC.
GAUGES
All gauges receive battery current through the
EMIC circuitry when the ignition switch is in the On
or Start positions. With the ignition switch in the Off
position battery current is not supplied to any
gauges, and the EMIC circuitry is programmed to
move all of the gauge needles back to the low end of
their respective scales. Therefore, the gauges do not
accurately indicate any vehicle condition unless the
ignition switch is in the On or Start positions. All of
the EMIC gauges, except the odometer, are air core
magnetic units. Two fixed electromagnetic coils are
located within each gauge. These coils are wrapped
at right angles to each other around a movable per-
manent magnet. The movable magnet is suspended
within the coils on one end of a pivot shaft, while the
gauge needle is attached to the other end of the
shaft. One of the coils has a fixed current flowing
through it to maintain a constant magnetic fieldstrength. Current flow through the second coil
changes, which causes changes in its magnetic field
strength. The current flowing through the second coil
is changed by the EMIC circuitry in response to mes-
sages received over the CCD data bus. The gauge
needle moves as the movable permanent magnet
aligns itself to the changing magnetic fields created
around it by the electromagnets.
The gauges are diagnosed using the EMIC self-di-
agnostic actuator test. (Refer to 8 - ELECTRICAL/
INSTRUMENT CLUSTER - DIAGNOSIS AND
TESTING). Proper testing of the CCD data bus and
the data bus message inputs to the EMIC that con-
trol each gauge require the use of a DRBIIItscan
tool. Refer to the appropriate diagnostic information.
Specific operation details for each gauge may be
found elsewhere in this service manual.
VACUUM-FLUORESCENT DISPLAY
The Vacuum-Fluorescent Display (VFD) module is
soldered to the EMIC circuit board. The display is
active with the ignition switch in the On or Start
positions, and inactive when the ignition switch is in
any other position. The VFD has several display
capabilities including odometer, trip odometer, and
an amber ªCRUISEº indication whenever the
optional speed control system is turned On. The
cruise indicator function of the VFD is automatically
enabled or disabled by the EMIC circuitry based
upon whether the vehicle is equipped with the speed
control option. An odometer/trip odometer switch on
the EMIC circuit board is used to control several of
the display modes. This switch is actuated manually
by depressing the odometer/trip odometer switch
knob that extends through the lower edge of the clus-
ter lens, just right of center. Actuating this switch
momentarily with the ignition switch in the On posi-
tion will toggle the VFD between the odometer and
trip odometer modes. The word ªTRIPº will also
appear in blue-green text when the VFD trip odome-
ter mode is active. Depressing the switch button for
about two seconds while the VFD is in the trip odom-
eter mode will reset the trip odometer value to zero.
Holding this switch depressed while turning the igni-
tion switch from the Off position to the On position
will activate the EMIC self-diagnostic actuator test.
The EMIC will automatically flash the odometer or
trip odometer information on and off if there is a loss
of CCD data bus communication. The VFD will also
display various information used in several diagnos-
tic procedures. Refer to the appropriate diagnostic
information for additional details on this VFD func-
tion.
8J - 4 INSTRUMENT CLUSTERBR/BE
INSTRUMENT CLUSTER (Continued)

The VFD is diagnosed using the EMIC self-diag-
nostic actuator test. (Refer to 8 - ELECTRICAL/IN-
STRUMENT CLUSTER - DIAGNOSIS AND
TESTING). Proper testing of the CCD data bus and
the data bus message inputs to the EMIC that con-
trol some of the VFD functions requires the use of a
DRBIIItscan tool. Refer to the appropriate diagnos-
tic information. Specific operation details for the
odometer and trip odometer functions of the VFD
may be found elsewhere in this service manual.
INDICATORS
Indicators are located in various positions within
the EMIC and are all connected to the EMIC circuit
board. The four-wheel drive indicator, high beam
indicator, washer fluid indicator, turn signal indica-
tors, and wait-to-start indicator are hard wired. The
brake indicator is controlled by CCD data bus mes-
sages from the Controller Anti-lock Brake (CAB) and
the hard wired park brake switch input to the EMIC.
The seatbelt indicator is controlled by the EMIC pro-
gramming, CCD data bus messages from the Airbag
Control Module (ACM), and the hard wired seat belt
switch input to the EMIC. The Malfunction Indicator
Lamp (MIL) is normally controlled by CCD data bus
messages from the Powertrain Control Module
(PCM); however, if the EMIC loses CCD data bus
communications, the EMIC circuitry will automati-
cally turn the MIL on, and flash the odometer VFD
on and off repeatedly until CCD data bus communi-
cation is restored. The EMIC uses CCD data bus
messages from the Powertrain Control Module
(PCM), the diesel engine only Engine Control Module
(ECM), the ACM, and the CAB to control all of the
remaining indicators. Different indicators are con-
trolled by different strategies; some receive fused
ignition switch output from the EMIC circuitry clus-
ter and have a switched ground, while others are
grounded through the EMIC circuitry and have a
switched battery feed.
In addition, certain indicators in this instrument
cluster are programmable or configurable. This fea-
ture allows the programmable indicators to be acti-
vated or deactivated with a DRBIIItscan tool, while
the configurable indicators will be automatically
enabled or disabled by the EMIC circuitry for com-
patibility with certain optional equipment. The only
programmable indicator for this model is the upshift
indicator. The cruise indicator, four-wheel drive indi-
cator, overdrive-off indicator, service reminder indica-
tor, and the transmission overtemp indicator are
automatically configured, either electronically or
mechanically.The hard wired indicators are diagnosed using con-
ventional diagnostic methods. The EMIC and CCD
bus message controlled indicator lamps are diagnosed
using the EMIC self-diagnostic actuator test. (Refer
to 8 - ELECTRICAL/INSTRUMENT CLUSTER -
DIAGNOSIS AND TESTING). Proper testing of the
CCD data bus and the data bus message inputs to
the EMIC that control each indicator lamp require
the use of a DRBIIItscan tool. Refer to the appro-
priate diagnostic information. Specific operation
details for each indicator may be found elsewhere in
this service manual.
CLUSTER ILLUMINATION
The EMIC has several illumination lamps that are
illuminated when the exterior lighting is turned on
with the headlamp switch. The illumination bright-
ness of these lamps is adjusted by the panel lamps
dimmer rheostat when the headlamp switch thumb-
wheel is rotated (down to dim, up to brighten). The
illumination lamps receive battery current through
the panel lamps dimmer rheostat and a fuse in the
JB on a fused panel lamps dimmer switch signal cir-
cuit. The illumination lamps are grounded at all
times.
In addition, an analog/digital (A/D) converter in
the EMIC converts the analog panel lamps dimmer
rheostat input from the headlamp switch to a digital
dimming level signal for controlling the lighting level
of the VFD. The EMIC also broadcasts this digital
dimming information as a message over the CCD
data bus for use by the Compass Mini-Trip Computer
(CMTC) in synchronizing the lighting level of its
VFD with that of the EMIC. The headlamp switch
thumbwheel also has a Parade position to provide a
parade mode. The EMIC monitors the request for
this mode through a hard wired day brightness sense
circuit input from the headlamp switch. In this mode,
the EMIC will override the selected panel dimmer
switch signal and send a message over the CCD data
bus to illuminate all vacuum fluorescent displays at
full brightness for easier visibility when driving in
daylight with the exterior lighting turned on. The
parade mode has no effect on the incandescent bulb
illumination intensity.
The hard wired cluster illumination lamps are
diagnosed using conventional diagnostic methods.
Proper testing of the VFD dimming level and the
CCD data bus dimming level message functions
requires the use of a DRBIIItscan tool. Refer to the
appropriate diagnostic information.
BR/BEINSTRUMENT CLUSTER 8J - 5
INSTRUMENT CLUSTER (Continued)

CHIME WARNING REQUESTS
The EMIC is programmed to request chime service
from the Central Timer Module (CTM) when certain
indicator lamps are illuminated. When the pro-
grammed conditions are met, the EMIC generates a
chime request signal and sends it over a hard wired
tone request circuit to the CTM. Upon receiving the
proper chime request, the CTM activates an integral
chime tone generator to provide the audible chime
tone to the vehicle operator. (Refer to 8 - ELECTRI-
CAL/CHIME/BUZZER - OPERATION). Proper test-
ing of the CTM and the EMIC chime requests
requires the use of a DRBIIItscan tool. Refer to the
appropriate diagnostic information.
DIAGNOSIS AND TESTING - INSTRUMENT
CLUSTER
If all of the instrument cluster gauges and/or indi-
cators are inoperative, refer to PRELIMINARY
DIAGNOSIS . If an individual gauge or Chrysler Col-
lision Detection (CCD) data bus message-controlled
indicator is inoperative, refer to ACTUATOR TEST .
If an individual hard wired indicator is inoperative,
refer to the diagnosis and testing information for
that specific indicator. If the instrument cluster
chime warning request function is inoperative, refer
to CHIME WARNING REQUEST DIAGNOSIS . If
the instrument cluster illumination lighting is inop-
erative, refer to CLUSTER ILLUMINATION DIAG-
NOSIS . If the instrument cluster Vacuum-
Fluorescent Display (VFD) dimmer service is
inoperative, use a DRBIIItscan tool to diagnose the
problem. Refer to the appropriate diagnostic proce-
dures. Refer to the appropriate wiring information.
The wiring 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.
NOTE: Certain indicators in this instrument cluster
are programmable. This feature allows those indica-
tors to be activated or deactivated with a DRBIIIT
scan tool for compatibility with certain optional
equipment. If the problem being diagnosed involves
improper illumination of the upshift indicator, use a
DRBIIITscan tool to be certain that the instrument
cluster has been programmed with the proper vehi-
cle equipment option settings.PRELIMINARY DIAGNOSIS
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) If the indicators operate, but none of the
gauges operate, go to Step 2. If all of the gauges and
the CCD data bus message-controlled indicators are
inoperative, go to Step 5.
(2) Check the fused B(+) fuse (Fuse 14 - 10
ampere) in the Junction Block (JB). If OK, go to Step
3. If not OK, repair the shorted circuit or component
as required and replace the faulty fuse.
(3) Check for battery voltage at the fused B(+) fuse
(Fuse 14 - 10 ampere) in the JB. If OK, go to Step 4.
If not OK, repair the open fused B(+) circuit between
the JB and the Power Distribution Center (PDC) as
required.
(4) Disconnect and isolate the battery negative
cable. Remove the instrument cluster. Connect the
battery negative cable. Check for battery voltage at
the fused B(+) circuit cavity of the instrument panel
wire harness connector (Connector C1) for the instru-
ment cluster. If OK, refer to ACTUATOR TEST . If
not OK, repair the open fused B(+) circuit between
the instrument cluster and the JB as required.
(5) Check the fused ignition switch output (st-run)
fuse (Fuse 17 - 10 ampere) in the JB. If OK, go to
Step 6. If not OK, repair the shorted circuit or com-
ponent as required and replace the faulty fuse.
(6) Turn the ignition switch to the On position.
Check for battery voltage at the fused ignition switch
output (st-run) fuse (Fuse 17 - 10 ampere) in the JB.
If OK, go to Step 7. If not OK, repair the open fused
ignition switch output (st-run) circuit between the
instrument cluster and the JB as required.
8J - 6 INSTRUMENT CLUSTERBR/BE
INSTRUMENT CLUSTER (Continued)