ESP DODGE RAM 2002 Service Owner's Manual

tem indicator lamp are visible in the lower left corner
of the a/c heater control face plate (Fig. 2).
The heated mirror switch, the heated mirror sys-
tem indicator lamp, the heated mirror system solid
state electronic control logic and timer circuitry and
the heated mirror relay cannot be repaired. If any of
these components is damaged or faulty, the entire a/c
heater control must be replaced. (Refer to 24 - HEAT-
ING & AIR CONDITIONING/CONTROLS/A/C
HEATER CONTROL - REMOVAL)
OPERATION
The momentary-type heated mirror switch provides
a hard-wired battery current signal to the heated
mirror system electronic control logic circuitry each
time it is depressed. In response to the heated mirror
switch input, the electronic control logic and timer
circuitry energizes or de-energizes the amber heated
mirror system indicator lamp next to the heated mir-
ror switch to indicate that the heated mirror system
is turned On or Off. The electronic control logic and
timer circuitry also energizes or de-energizes the
heated mirror relay, which controls the feed of elec-
trical current to the outside mirror heating grids.
The heated mirror system electronic control logic
and timer circuitry is programmed to turn the heated
mirror system Off automatically after about fifteen
minutes of operation. If the heated mirror system is
turned On a second time following an initial time-out
event during the same ignition switch cycle, the
heated mirror system electronic control logic and
timer circuit is programmed to turn the system Offautomatically after about five minutes. When the
electronic control logic and timer circuit detects that
a programmed time interval has elapsed, it will auto-
matically de-energize the heated mirror system indi-
cator lamp and the heated mirror relay. The heated
mirror system will also be turned Off if the heated
mirror switch is depressed while the system is
turned On, or if the ignition switch is turned to the
Off or Accessory positions.
DIAGNOSIS AND TESTING - HEATED MIRROR
SWITCH
The heated mirror switch, the solid state electronic
heated mirror system control logic and timer cir-
cuitry, the heated mirror system indicator lamp and
the heated mirror relay are all integral to the a/c
heater control. For circuit descriptions and diagrams
(Refer to Appropriate Wiring Information).
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) Check the fused ignition switch output (run/
start) fuse in the Junction Block (JB). If OK, go to
Step 2. If not OK, repair the shorted circuit or com-
ponent as required and replace the faulty fuse.
(2) Turn the ignition switch to the On position.
Check for battery voltage at the fused ignition switch
output (run/start) fuse in the JB. If OK, go to Step 3.
If not OK, repair the open circuit to the ignition
switch as required.
(3) Disconnect and isolate the battery negative
cable. Disconnect the 3-way instrument panel wire
harness connector for the heated mirror switch from
the heated mirror switch connector receptacle on the
back of the a/c heater control. Check for continuity
between the ground circuit cavity of the wire harness
connector and a good ground. There should be conti-
nuity. If OK, go to Step 4. If not OK, repair the open
ground circuit to ground as required.
(4) Reconnect the battery negative cable. Turn the
ignition switch to the On position. Check for battery
voltage at the fused ignition switch output (run/start)
circuit cavity of the 3-way instrument panel wire
Fig. 2 HEATED MIRROR SWITCH
1 - A/C HEATER CONTROL
2 - HEATED MIRROR SWITCH
3 - HEATED MIRROR SYSTEM INDICATOR LAMP
BR/BEHEATED MIRRORS 8G - 3
MIRROR SWITCH (Continued)

²Heated Seat Elements- Four heated seat ele-
ments are used per vehicle, one for each front seat
back and one for each front seat cushion. The ele-
ments are integral to the individual front seat and
seat back cushions and cannot be removed once
installed at the factory. Service replacement seat
heating elements are available, without having to
replace the entire seat cushion or trim cover. Refer to
the procedure in this section.
²Heated Seat Sensors- Two heated seat sen-
sors are used per vehicle, one for each front seat. The
sensors are integral to the individual front seat heat-
ing elements and cannot be removed once installed at
the factory. Service replacement seat heating ele-
ments with the sensors are available, without having
to replace the entire seat cushion or trim cover. Refer
to the procedure in this section.
²Heated Seat Relay- The heated seat relay
controls the battery voltage and current supply to the
heated seat module and the rest of the heated seat
system. The heated seat relay is mounted in the
junction block and is not different than the other
relays used throughout the vehicle. Refer to the
Power Distribution section of the service manual for
more information on standard ISO relays.
Following are general descriptions of the major
components in the heated seat system. See the own-
er's manual in the vehicle glove box for more infor-
mation on the features, use and operation of the
heated seat system. Refer toWiring Diagramsfor
the location of complete heated seat system wiring
diagrams.
OPERATION
The heated seat module receives fused battery cur-
rent through the energized heated seat relay in the
Junction Block (JB) only when the engine is running.
The heated seat switches receive battery current
through fuse #2 in the Junction Block only when the
ignition switch is in the On position. The heated seat
module shares a common ground circuit with each of
the heated seat elements. The heated seat elements
will only operate when the surface temperature of
the seat cushion is below the designed temperature
set points of the system.
The heated seat system will also be turned off
automatically whenever the ignition switch is turned
to any position except On or if the engine quits run-
ning. If the ignition switch is turned to the Off posi-
tion or if the engine quits running while a heated
seat is turned ON, the heated seat will remain Off
after the engine is restarted until a heated seat
switch is depressed again.
The heated seat module monitors inputs from the
heated seat sensors and the heated seat switches. In
response to these inputs the heated seat module usesits internal programming to control outputs to the
heated seat elements in both front seats and to con-
trol the heated seat LED indicator lamps located in
both of the heated seat switches. The heated seat
module is also programmed to provide a self-diagnos-
tic capability. When the module detects certain fail-
ures within the heated seat system, it will provide a
visual indication of the failure by flashing the indica-
tor lamps in the heated seat switches. The heated
seat module will automatically turn off the heated
seat elements if it detects a short or open in the
heated seat element circuit or a heated seat sensor
value that is out of range.
DIAGNOSIS AND TESTING - HEATED SEAT
SYSTEM
HEATED SEAT SYSTEM SELF-DIAGNOSIS
The heated seat system is capable of performing
some self-diagnostics. The following table depicts the
various monitored failures which will be reported to
the vehicle operator or technician by flashing the
individual heated seat switch Light Emitting Diode
(LED) indicator lamps. Refer to the Heated Seat Sys-
tem Self-Diagnosis table for failure identification.
The driver side heated seat switch indicator lamps
will flash if a failure occurs in the driver side heated
seat, and the passenger side heated seat switch indi-
cator lamps will flash for a passenger side heated
seat failure. If a monitored heated seat system fail-
ure occurs, the switch indicator lamps will flash at a
pulse rate of about one-half second on, followed by
about one-half second off for a duration of about one
minute after the switch for the faulty heated seat is
depressed in either the Low or High direction. This
process will repeat every time the faulty heated seat
switch is actuated until the problem has been cor-
rected.
Heated Seat System Self-Diagnosis
Monitored FailureSwitch High
Indicator LampSwitch Low
Indicator Lamp
Heated Seat
Element ShortedFlashing Flashing
Heated Seat
Element OpenFlashing Off
Heated Seat
Sensor Value Out
of RangeOff Flashing
8G - 6 HEATED SEAT SYSTEMBR/BE
HEATED SEAT SYSTEM (Continued)

B(+) to heated seat module circuit to the heated seat
module as required.
(4) The coil battery terminal (86) is connected to
the electromagnet in the relay. It is connected to bat-
tery voltage and should be hot at all times. Check for
battery voltage at the cavity for relay terminal 86. If
OK, go to Step 5. If not OK, repair the open circuit to
the fused B(+) fuse in the PDC as required.
(5) The coil ground terminal (85) is connected to
the electromagnet in the relay. It is grounded by the
premium version of the Central Timer Module (CTM)
in response to an engine speed message received over
the Chrysler Collision Detection (CCD) data bus from
the Powertrain Control Module (PCM) when the
engine is running. Check for continuity between the
cavity for relay terminal 85 and the heated seat relay
control circuit cavity of the CTM wire harness con-
nector. There should be continuity at all times. If OK,
use a DRBIIItscan tool and the proper diagnostic
procedures manual to test the operation of the CTM
and CCD data bus. If not OK, repair the open heated
seat relay control circuit as required.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the fuse access panel by inserting a
finger in the finger recess molded into the panel and
then pulling the panel sharply away from the left
outboard end of the instrument panel.
(3) The heated seat relay is located on the forward
side of the Junction Block (JB), just above the com-
bination flasher (Fig. 16) .
(4) Grasp the heated seat relay firmly and pull it
straight out from the JB.
INSTALLATION
(1) Position the heated seat relay in the proper
receptacle in the JB.
(2) Align the heated seat relay terminals with the
terminal cavities in the JB receptacle.
(3) Push in firmly on the heated seat relay until
the terminals are fully seated in the terminal cavities
in the JB receptacle.
(4) Insert the tabs on the forward edge of the fuse
access panel in the notches on the forward edge of
the instrument panel fuse access panel opening.
(5) Press the rear edge of the fuse access panel in
toward the instrument panel until the panel snaps
back into place.
(6) Reconnect the battery negative cable.
PASSENGER SEAT HEATER
SWITCH
DESCRIPTION
The heated seat switches are both mounted in a
heated seat switch bezel (Fig. 17), which replaces the
standard equipment cubby bin located in the lower
right corner of the instrument cluster bezel next to
the radio receiver. The two switches are snapped into
the mounting holes of the heated seat switch bezel,
and the heated seat switch bezel is secured with
three screws to the instrument panel. The mounts for
the heated seat switch bezel are concealed behind the
instrument cluster bezel. The two heated seat
switches are identical in appearance and construc-
tion, except for the location of a keyway in the single
connector receptacle on the back of each switch. The
instrument panel wire harness connectors for the
heated seat switches are keyed to match the connec-
tor receptacles on the switches so that the two
heated seat switches can only be connected to the
proper heated seat electrical.
The momentary, bidirectional rocker-type heated
seat switch provides a resistor-multiplexed signal to
the heated seat module on the mux circuit. Each
switch has a center neutral position and momentary
Low and High positions so that both the driver and
Fig. 16 Heated Seat
1 - JUNCTION BLOCK
2 - HEATED SEAT RELAY
3 - INSTRUMENT PANEL
4 - COMBINATION FLASHER
8G - 16 HEATED SEAT SYSTEMBR/BE
HEATED SEAT RELAY (Continued)

HORN
TABLE OF CONTENTS
page page
HORN
DESCRIPTION..........................1
OPERATION............................1
HORN
DESCRIPTION..........................2
OPERATION............................2
DIAGNOSIS AND TESTING - HORN..........2
REMOVAL.............................2
INSTALLATION..........................3
HORN RELAY
DESCRIPTION..........................3OPERATION............................3
DIAGNOSIS AND TESTING - HORN RELAY....3
REMOVAL.............................4
INSTALLATION..........................4
HORN SWITCH
DESCRIPTION..........................4
OPERATION............................5
DIAGNOSIS AND TESTING - HORN SWITCH . . . 5
REMOVAL.............................5
HORN
DESCRIPTION
An electric horn system is standard factory-in-
stalled equipment on this model. Two horn systems
are offered on this model. The standard equipment
horn system features a single low-note electromag-
netic horn unit, while the optional dual horn system
features one low-note horn unit and one high-note
horn unit. Both horn systems use a non-switched
source of battery current so that the system will
remain functional, regardless of the ignition switch
position. The horn system includes the following com-
ponents:
²Clockspring
²High-line or premium Central Timer Module
(CTM)
²Horn(s)
²Horn relay
²Horn switch
(Refer to 8 - ELECTRICAL/RESTRAINTS/CLOCK-
SPRING - DESCRIPTION) for more information on
this component. (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/BODY CONTROL/
CENTRAL TIMER MODUL - DESCRIPTION) for
more information on this component. Refer to the
appropriate wiring information. The wiring informa-
tion includes wiring diagrams, proper wire and con-
nector 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. Following are general
descriptions of the remaining major components in
the horn system.
OPERATION
Each horn system is activated by a horn switch
concealed beneath the driver side airbag module trim
cover in the center of the steering wheel. Depressing
the center of the driver side airbag module trim cover
closes the horn switch. Closing the horn switch acti-
vates the horn relay. The activated horn relay then
switches the battery current needed to energize the
horn(s).
Refer to the owner's manual in the vehicle glove
box for more information on the features, use and
operation of the horn system.
CENTRAL TIMER MODULE
The high-line or premium Central Timer Module
(CTM) can also operate the horn system. A high-line
CTM is used on high-line versions of this vehicle. A
premium CTM is used on vehicles equipped with the
optional heated seats. The CTM combines the func-
tions of a chime/buzzer module, an intermittent wipe
module, an illuminated entry module, a remote key-
less entry module, and a vehicle theft security sys-
tem module in a single unit.
The high-line or premium CTM also controls and
integrates many of the additional electronic functions
and features included on models with this option.
The horn relay is one of the hard wired outputs of
the CTM. The high-line or premium CTM is pro-
grammed to energize or de-energize the horn relay in
response to certain inputs from the Vehicle Theft
Security System (VTSS) and/or the Remote Keyless
Entry (RKE) system.
(Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/BODY CONTROL/CENTRAL
TIMER MODUL - DESCRIPTION) for more informa-
tion on the high-line or premium CTM. (Refer to 8 -
BR/BEHORN 8H - 1

nector at all times. If OK, go to Step 4. If not OK,
repair the open circuit to the horn(s) as required.
(4) The coil battery terminal (86) is connected to
the electromagnet in the relay. It is connected to bat-
tery voltage and should be hot at all times. Check for
battery voltage at the cavity for relay terminal 86. If
OK, go to Step 5. If not OK, repair the open circuit to
the fuse in the PDC as required.
(5) The coil ground terminal (85) is connected to
the electromagnet in the relay. It is grounded
through the horn switch when the horn switch is
depressed. On vehicles equipped with the Vehicle
Theft Security System (VTSS), the horn relay coil
ground terminal can also be grounded by the Central
Timer Module (CTM) in response to certain inputs
related to the VTSS or Remote Keyless Entry (RKE)
system. Check for continuity to ground at the cavity
for relay terminal 85. There should be continuity
with the horn switch depressed, and no continuity
with the horn switch released. If not OK, (Refer to 8
- ELECTRICAL/HORN/HORN SWITCH - DIAGNO-
SIS AND TESTING).
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the cover from the Power Distribution
Center (PDC) (Fig. 3) .
(3) See the fuse and relay layout label affixed to
the underside of the PDC cover for horn relay iden-
tification and location.
(4) Remove the horn relay from the PDC.
INSTALLATION
(1) See the fuse and relay layout label affixed to
the underside of the PDC cover for the proper horn
relay location.
(2) Position the horn relay in the proper receptacle
in the PDC.
(3) Align the horn relay terminals with the termi-
nal cavities in the PDC receptacle.
(4) Push down firmly on the horn relay until the
terminals are fully seated in the terminal cavities in
the PDC receptacle.
(5) Install the cover onto the PDC.
(6) Reconnect the battery negative cable.
HORN SWITCH
DESCRIPTION
A center-blow, normally open, resistive membrane-
type horn switch is secured with heat stakes to the
back side of the driver side airbag module trim cover
in the center of the steering wheel (Fig. 4) . The
switch consists of two plastic membranes, one that is
flat and one that is slightly convex. These two mem-
branes are secured to each other around the perime-
ter. Inside the switch, the centers of the facing
surfaces of these membranes each has a grid made
with an electrically conductive material applied to it.
One of the grids is connected to a circuit that pro-
vides it with continuity to ground at all times. The
grid of the other membrane is connected to the horn
relay control circuit.
The steering wheel and steering column must be
properly grounded in order for the horn switch to
function properly. The horn switch is only serviced as
a part of the driver side airbag module trim cover. If
Fig. 2 Horn Relay
TERMINAL LEGEND
NUMBER IDENTIFICATION
30 COMMON FEED
85 COIL GROUND
86 COIL BATTERY
87 NORMALLY OPEN
87A NORMALLY CLOSED
Fig. 3 Power Distribution Center
1 - COVER
2 - POWER DISTRIBUTION CENTER
8H - 4 HORNBR/BE
HORN RELAY (Continued)

the ECM relating engine speed and crankshaft posi-
tion.
The sensor detects machined notches on the rear
face of the camshaft drive gear (Fig. 7) to sense
engine speed.
The CMP also detects an area on the camshaft
drive gear that has no notch (Fig. 7). When the sen-
sor passes this area, it tells the Engine Control Mod-
ule (ECM) that Top Dead Center (TDC) of the
number 1 cylinder is occurring. The ECM will then
adjust fuel timing accordingly.
As the tip of the sensor passes the notches, the
interruption of magnetic field causes voltage changes
from 5 volts to 0 volts.
OPERATION - 5.9L
The sensor contains a hall effect device called a
sync signal generator to generate a fuel sync signal.
This sync signal generator detects a rotating pulse
ring (shutter) on the distributor shaft. The pulse ring
rotates 180 degrees through the sync signal genera-
tor. Its signal is used in conjunction with the Crank-
shaft Position (CKP) sensor to differentiate between
fuel injection and spark events. It is also used to syn-
chronize the fuel injectors with their respective cylin-
ders.
When the leading edge of the pulse ring (shutter)
enters the sync signal generator, the following occurs:
The interruption of magnetic field causes the voltageto switch high resulting in a sync signal of approxi-
mately 5 volts.
When the trailing edge of the pulse ring (shutter)
leaves the sync signal generator, the following occurs:
The change of the magnetic field causes the sync sig-
nal voltage to switch low to 0 volts.
OPERATION - 8.0L
The CMP sensor is used in conjunction with the
crankshaft position sensor to differentiate between
fuel injection and spark events. It is also used to syn-
chronize the fuel injectors with their respective cylin-
ders. The sensor generates electrical pulses. These
pulses (signals) are sent to the Powertrain Control
Module (PCM). The PCM will then determine crank-
shaft position from both the camshaft position sensor
and crankshaft position sensor.
A low and high area are machined into the cam-
shaft drive gear (Fig. 8). The sensor is positioned in
the timing gear cover so that a small air gap (Fig. 8)
exists between the face of sensor and the high
machined area of cam gear.
When the cam gear is rotating, the sensor will
detect the machined low area. Input voltage from the
sensor to the PCM will then switch from a low
(approximately 0.3 volts) to a high (approximately 5
volts). When the sensor detects the high machined
area, the input voltage switches back low to approx-
imately 0.3 volts.
REMOVAL
REMOVAL - DIESEL
The camshaft position sensor (CMP) is located
below the fuel injection pump (Fig. 9). It is attached
to the back of the timing gear cover housing.
(1) Disconnect both negative cables from both bat-
teries.
(2) Clean area around CMP.
(3) Disconnect electrical at CMP (Fig. 9).
(4) Remove CMP mounting bolt. Bolt head is
female-hex (Fig. 10).
(5) Remove CMP from engine by twisting and pull-
ing straight back.
(6) Discard CMP o-ring (Fig. 10).
REMOVAL - 5.9L
The camshaft position sensor is located in the dis-
tributor (Fig. 11).
Distributor removal is not necessary to remove
camshaft position sensor.
(1) Remove air cleaner assembly.
(2) Disconnect negative cable from battery.
(3) Remove distributor cap from distributor (two
screws).
Fig. 7 Notches at Rear Of Camshaft Drive Gear
1 - CAMSHAFT DRIVE GEAR
2 - NOTCHES
3 - CAMSHAFT POSITION SENSOR (CKP)
4 - NO NOTCH
BR/BEIGNITION CONTROL 8I - 7
CAMSHAFT POSITION SENSOR (Continued)

in which they were removed from the engine. A sin-
gle plug displaying an abnormal condition indicates
that a problem exists in the corresponding cylinder.
Replace spark plugs at the intervals recommended in
Group O, Lubrication and Maintenance
Spark plugs that have low mileage may be cleaned
and reused if not otherwise defective, carbon or oil
fouled. Also refer to Spark Plug Conditions.
CAUTION: Never use a motorized wire wheel brush
to clean the spark plugs. Metallic deposits will
remain on the spark plug insulator and will cause
plug misfire.
DIAGNOSIS AND TESTING - SPARK PLUG
CONDITIONS
NORMAL OPERATING
The few deposits present on the spark plug will
probably be light tan or slightly gray in color. This is
evident with most grades of commercial gasoline
(Fig. 28). There will not be evidence of electrode
burning. Gap growth will not average more than
approximately 0.025 mm (.001 in) per 3200 km (2000
miles) of operation. Spark plugs that have normalwear can usually be cleaned, have the electrodes
filed, have the gap set and then be installed.
Some fuel refiners in several areas of the United
States have introduced a manganese additive (MMT)
for unleaded fuel. During combustion, fuel with MMT
causes the entire tip of the spark plug to be coated
with a rust colored deposit. This rust color can be
misdiagnosed as being caused by coolant in the com-
bustion chamber. Spark plug performance may be
affected by MMT deposits.
COLD FOULING/CARBON FOULING
Cold fouling is sometimes referred to as carbon
fouling. The deposits that cause cold fouling are basi-
cally carbon (Fig. 28). A dry, black deposit on one or
two plugs in a set may be caused by sticking valves
or defective spark plug cables. Cold (carbon) fouling
of the entire set of spark plugs may be caused by a
clogged air cleaner element or repeated short operat-
ing times (short trips).
WET FOULING OR GAS FOULING
A spark plug coated with excessive wet fuel or oil
is wet fouled. In older engines, worn piston rings,
leaking valve guide seals or excessive cylinder wear
can cause wet fouling. In new or recently overhauled
engines, wet fouling may occur before break-in (nor-
mal oil control) is achieved. This condition can usu-
ally be resolved by cleaning and reinstalling the
fouled plugs.
OIL OR ASH ENCRUSTED
If one or more spark plugs are oil or oil ash
encrusted (Fig. 29), evaluate engine condition for the
Fig. 27 Spark Plug Cable OrderÐ8.0L V-10 Engine
Fig. 28 Normal Operation and Cold (Carbon) Fouling
1 - NORMAL
2 - DRY BLACK DEPOSITS
3 - COLD (CARBON) FOULING
BR/BEIGNITION CONTROL 8I - 17
SPARK PLUG (Continued)

CAUTION: Do not leave any one spark plug cable
disconnected for longer than necessary during test-
ing. This may cause possible heat damage to the
catalytic converter. Total test time must not exceed
ten minutes.
With the engine running, remove spark plug cable
from spark plug (one at a time) and hold next to a
good engine ground. If the cable and spark plug are
in good condition, the engine rpm should drop and
the engine will run poorly. If engine rpm does not
drop, the cable and/or spark plug may not be operat-
ing properly and should be replaced. Also check
engine cylinder compression.
With the engine not running, connect one end of a
test probe to a good ground. Start the engine and run
the other end of the test probe along the entire
length of all spark plug cables. If cables are cracked
or punctured, there will be a noticeable spark jump
from the damaged area to the test probe. The cable
running from the ignition coil to the distributor cap
can be checked in the same manner. Cracked, dam-
aged or faulty cables should be replaced with resis-
tance type cable. This can be identified by the words
ELECTRONIC SUPPRESSION printed on the cable
jacket.
Use an ohmmeter to test for open circuits, exces-
sive resistance or loose terminals. If equipped,
remove the distributor cap from the distributor.Do
not remove cables from cap.Remove cable from
spark plug. Connect ohmmeter to spark plug termi-
nal end of cable and to corresponding electrode in
distributor cap. Resistance should be 250 to 1000
Ohms per inch of cable. If not, remove cable from dis-
tributor cap tower and connect ohmmeter to the ter-
minal ends of cable. If resistance is not within
specifications as found in the SPARK PLUG CABLE
RESISTANCE chart, replace the cable. Test all spark
plug cables in this manner.
SPARK PLUG CABLE RESISTANCE
MINIMUM MAXIMUM
250 Ohms Per Inch 1000 Ohms Per Inch
3000 Ohms Per Foot 12,000 Ohms Per Foot
To test ignition coil-to-distributor cap cable, do not
remove the cable from the cap. Connect ohmmeter to
rotor button (center contact) of distributor cap and
terminal at ignition coil end of cable. If resistance is
not within specifications as found in the Spark Plug
Cable Resistance chart, remove the cable from the
distributor cap. Connect the ohmmeter to the termi-
nal ends of the cable. If resistance is not within spec-
ifications as found in the Spark Plug CableResistance chart, replace the cable. Inspect the igni-
tion coil tower for cracks, burns or corrosion.
REMOVAL
CAUTION: When disconnecting a high voltage cable
from a spark plug or from the distributor cap, twist
the rubber boot slightly (1/2 turn) to break it loose
(Fig. 37). Grasp the boot (not the cable) and pull it
off with a steady, even force.
INSTALLATION
Install cables into the proper engine cylinder firing
order (Fig. 38) or (Fig. 39).
Fig. 37 Cable Removal
1 - SPARK PLUG CABLE AND BOOT
2 - SPARK PLUG BOOT PULLER
3 - TWIST AND PULL
4 - SPARK PLUG
Fig. 38 Engine Firing OrderÐ5.9L V-8 Engines
BR/BEIGNITION CONTROL 8I - 21
SPARK PLUG CABLE (Continued)

²Check Gauges Indicator
²Cruise Indicator (Odometer VFD)
²Four-Wheel Drive Indicator
²High Beam Indicator
²Low Fuel Indicator
²Washer Fluid Indicator
²Malfunction Indicator Lamp (MIL)
²Overdrive-Off Indicator
²Seatbelt Indicator
²Service Reminder Indicator (SRI)
²Transmission Overtemp Indicator
²Turn Signal (Right and Left) Indicators
²Upshift Indicator
²Wait-To-Start Indicator (Diesel Only)
²Water-In-Fuel Indicator (Diesel Only)
Some of these indicators are either programmable
or automatically configured when the EMIC is con-
nected to the vehicle electrical system. This feature
allows those indicators to be activated or deactivated
for compatibility with certain optional equipment.
The EMIC also includes a provision for mounting the
automatic transmission gear selector indicator in the
lower right corner of the cluster. The spring-loaded,
cable driven, mechanical gear selector indicator gives
an indication of the transmission gear that has been
selected with the automatic transmission gear selec-
tor lever. The gear selector indicator pointer is easily
visible through an opening provided in the front of
the cluster overlay, and is also lighted by the cluster
illumination lamps for visibility at night. Models
equipped with a manual transmission have a block-
out plate installed in place of the gear selector indi-
cator.
Cluster illumination is accomplished by adjustable
incandescent back lighting, which illuminates the
gauges for visibility when the exterior lighting is
turned on. The EMIC high beam indicator, turn sig-
nal indicators, and wait-to-start indicator are also
illuminated by dedicated incandescent bulbs. The
remaining indicators in the EMIC are each illumi-
nated by a dedicated Light Emitting Diode (LED)
that is soldered onto the electronic circuit board.
Each of the incandescent bulbs is secured by an inte-
gral bulb holder to the electronic circuit board from
the back of the cluster housing.
Hard wired circuitry connects the EMIC to the
electrical system of the vehicle. These hard wired cir-
cuits are integral to several wire harnesses, which
are routed throughout the vehicle and retained by
many different methods. These circuits may be con-
nected to each other, to the vehicle electrical system
and to the EMIC through the use of a combination of
soldered splices, splice block connectors, and many
different types of wire harness terminal connectors
and insulators. Refer to the appropriate wiring infor-
mation. The wiring information includes wiring dia-grams, proper wire and connector repair procedures,
further details on wire harness routing and reten-
tion, as well as pin-out and location views for the
various wire harness connectors, splices and grounds.
The EMIC modules for this model are serviced only
as complete units. The EMIC module cannot be
adjusted or repaired. If a gauge, an LED indicator,
the VFD, the electronic circuit board, the circuit
board hardware, the cluster overlay, or the EMIC
housing are damaged or faulty, the entire EMIC mod-
ule must be replaced. The cluster lens and hood unit,
the rear cluster housing cover, the automatic trans-
mission gear selector indicator, and the incandescent
lamp bulbs with holders are available for individual
service replacement.
OPERATION
The ElectroMechanical Instrument Cluster (EMIC)
is designed to allow the vehicle operator to monitor
the conditions of many of the vehicle components and
operating systems. The gauges and indicators in the
EMIC provide valuable information about the various
standard and optional powertrains, fuel and emis-
sions systems, cooling systems, lighting systems,
safety systems and many other convenience items.
The EMIC is installed in the instrument panel so
that all of these monitors can be easily viewed by the
vehicle operator when driving, while still allowing
relative ease of access for service. The microproces-
sor-based EMIC hardware and software uses various
inputs to control the gauges and indicators visible on
the face of the cluster. Some of these inputs are hard
wired, but most are in the form of electronic mes-
sages that are transmitted by other electronic mod-
ules over the Chrysler Collision Detection (CCD) data
bus network. (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/COMMUNICATION
- OPERATION).
The EMIC microprocessor smooths the input data
using algorithms to provide gauge readings that are
accurate, stable and responsive to operating condi-
tions. These algorithms are designed to provide
gauge readings during normal operation that are con-
sistent with customer expectations. However, when
abnormal conditions exist, such as low/high battery
voltage, low oil pressure, or high coolant tempera-
ture, the algorithm drives the gauge pointer to an
extreme position and the microprocessor turns on the
Check Gauges indicator to provide a distinct visual
indication of a problem to the vehicle operator. The
instrument cluster circuitry may also generate a
hard wired chime tone request to the Central Timer
Module (CTM) when it monitors certain conditions or
inputs, in order to provide the vehicle operator with
an audible alert.
BR/BEINSTRUMENT CLUSTER 8J - 3
INSTRUMENT CLUSTER (Continued)

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 field
strength. Current flow through the second coil
changes, which causes changes in its magnetic fieldstrength. 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.
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-
8J - 4 INSTRUMENT CLUSTERBR/BE
INSTRUMENT CLUSTER (Continued)