Electrical JEEP LIBERTY 2002 KJ / 1.G Manual PDF

(4) Connect the negative lead of the voltmeter to
the right side bus bar and touch each grid line at its
midpoint with the positive lead (Fig. 3). A reading of
approximately six volts indicates a line is good. A
reading of zero volts indicates a break in the grid
line between the midpoint of the grid line and the
left side bus bar. A reading of ten to fourteen volts
indicates a break between the midpoint of the grid
line and the right side bus bar. Move the positive
lead on the grid line towards the break and the volt-
age reading will change as soon as the break is
crossed.
REAR WINDOW DEFOGGER
RELAY
DESCRIPTION
The rear window defogger relay is a International
Standards Organization (ISO)-type relay. The rear
window defogger relay is a electromechanical device
that switches fused battery current to the rear glass
and outside mirror heating grids, and the indicator
lamp of the defogger switch, when the HVAC control
head rear window defogger timer and logic circuitrygrounds the relay coil. (Refer to 8 - ELECTRICAL/
HEATED GLASS/REAR WINDOW DEFOGGER
RELAY - DIAGNOSIS AND TESTING)
The rear window defogger relay is located in the
junction block, on the left side of the instrument
panel inboard to the center of the vehicle (just to the
left and above the brake pedal or behind the knee
blocker). The rear window defogger relay cannot be
repaired and, if faulty or damaged, it must be
replaced.
OPERATION
The ISO relay consists of an electromagnetic coil, a
resistor or diode, and three (two fixed and one mov-
able) electrical contacts. The movable (common feed)
relay contact is held against one of the fixed contacts
(normally closed) by spring pressure. When the elec-
tromagnetic coil is energized, it draws the movable
contact away from the normally closed fixed contact,
and holds it against the other (normally open) fixed
contact.
When the electromagnetic coil is de-energized,
spring pressure returns the movable contact to the
normally closed position. The resistor is connected in
parallel with the electromagnetic coil in the relay,
and helps to dissipate voltage spikes that are pro-
duced when the coil is de-energized.
DIAGNOSIS AND TESTING - REAR WINDOW
DEFOGGER RELAY
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 AN ACCIDENTAL
AIRBAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
RELAY TEST
The defogger relay (Fig. 4) is located in the junc-
tion block, on the left side of the instrument panel
inboard to the center of the vehicle (just to the right
and above the brake pedal or behind the knee
blocker). Remove the defogger relay from the junction
block to perform the following tests:
(1) A relay in the de-energized position should
have continuity between terminals 87A and 30, and
Fig. 3 REAR WINDOW DEFOGGER
1 - DEFOGGER BACKGLASS
2 - HEATED GLASS CONNECTOR9A9
3 - HINDGE MOUNTING SCREWS (2)
4 - HINDGE (LEFT SIDE)
5 - HINDGE MOUNTING SCREWS (2)
6 - HINDGE (RIGHT SIDE)
7 - HEATED GLASS CONNECTOR9B9
8 - BACKGLASS DEFOGGER GRID
8G - 6 WINDOW DEFOGGERKJ
REAR WINDOW DEFOGGER GRID (Continued)

REAR WINDOW DEFOGGER
SWITCH
DESCRIPTION
The rear window defogger switch is installed in the
instrument panel HVAC contol head assembly. The
momentary-type switch provides a hard-wired ground
signal to the HVAC control head each time it is
depressed. The instrument cluster rear window
defogger timer and logic circuitry responds by ener-
gizing or de-energizing the rear window defogger
relay.
OPERATION
Energizing the rear window defogger relay pro-
vides electrical current to the rear window defogger
grid and, if the vehicle is so equipped, the outside
rear view mirror heating grids. An amber indicator
lamp in the defogger switch, which lights to indicate
when the defogger system is turned On, is also pow-
ered by the defogger relay output.
The defogger switch illumination lamp and indica-
tor lamp bulbs are serviceable. The defogger switch
cannot be repaired and, if faulty or damaged the
entire HVAC control head assembly must be
replaced.
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - REAR WINDOW
DEFOGGER SWITCH
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 AN ACCIDENTAL
AIRBAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) Disconnect and isolate the battery negative
cable. Remove the HVAC control head assembly from
the instrument panel and unplug the defogger switch
wire harness connector-B.
(2) Check for continuity between the ground cir-
cuit cavity of the defogger switch wire harness con-nector and a good ground. There should be
continuity. If OK, go to Step 3. If not OK, repair the
open circuit as required.
(3) Check for continuity between the ground cir-
cuit terminal and the rear window defogger switch
sense circuit terminal on the back of the defogger
switch housing (Fig. 5). There should be momentary
continuity as the defogger switch button is depressed,
and then no continuity. If OK, (Refer to 8 - ELEC-
TRICAL/HEATED GLASS/REAR WINDOW DEFOG-
GER SWITCH - DIAGNOSIS AND TESTING -
INSTRUMENT CLUSTER REAR WINDOW DEFOG-
GER FUNCTION) If not OK, replace the faulty
switch (Fig. 5).
(4) Check switch position continuity between:
CONTACT PINS
1 - OFF LAMPS A-1 - A-7
2 - ON MOMENTARY B-6 - B-8
3 - ILLUMINATION LAMP A-7 - A-1
4 - INDICATOR LAMP B-12 - B-7
Fig. 5 A/C HEATER CONTROL HEAD (Rear View)
1 - A/C HEATER CONTROL HEAD
2 - A/C HEATER CONTROL HEAD LIGHT
3 - REAR WINDOW DEFOGGER SWITCH AND TEMPERATURE
BLEND DOOR- CONNECTOR B (12 PIN)
4 - A/C HEATER CONTROL HEAD LIGHT
5 - MODE SELECT CONTROL
6 - BLOWER SPEED CONTROL- CONNECTOR A (7 PIN)
7 - MOUNTING SCREWS (4)
8G - 8 WINDOW DEFOGGERKJ

HEATED SEAT SYSTEM
TABLE OF CONTENTS
page page
HEATED SEAT SYSTEM
DESCRIPTION.........................10
OPERATION...........................10
DIAGNOSIS AND TESTING - HEATED SEAT
SYSTEM............................11
DRIVER SEAT HEATER SWITCH
DESCRIPTION.........................11
OPERATION...........................12
DIAGNOSIS AND TESTING - HEATED SEAT
SWITCH............................12
REMOVAL.............................13
INSTALLATION.........................13
HEATED SEAT ELEMENT
DESCRIPTION.........................13OPERATION...........................13
DIAGNOSIS AND TESTING - HEATED SEAT
ELEMENT...........................13
HEATED SEAT SENSOR
DIAGNOSIS AND TESTING - HEATED SEAT
SENSOR............................14
PASSENGER SEAT HEATER SWITCH
DESCRIPTION.........................14
OPERATION...........................14
DIAGNOSIS AND TESTING - HEATED SEAT
SWITCH............................14
REMOVAL.............................15
INSTALLATION.........................15
HEATED SEAT SYSTEM
DESCRIPTION
Individually controlled electrically heated front
seats are available on models that are also equipped
with the optional leather trim package. Vehicles with
this option can be visually identified by the two sep-
arate heated seat switches mounted on the outboard
seat cushion side shields. The heated seat system
allows the front seat driver and passenger to select
from two different levels of supplemental electrical
seat heating, or no seat heating to suit their individ-
ual comfort requirements. The heated seat system for
this vehicle includes the following major components:
²Heated Seat Switches- Two heated seat
switches are used per vehicle, including two Light-
Emitting Diode (LED) indicator lamps and an incan-
descent back lighting bulb for each switch. One
switch for the driver and one for the passenger front
seats. The switches are mounted on the outboard
seat cushion side shields.
²Heated Seat Module- also referred to as the
Seat Heat Interface Module (SHIM), this module con-
tains the solid state electronic control and diagnostic
logic circuitry for the heated seat system. One heated
seat module is used per vehicle and is mounted
under the left front seat cushion. Refer to the Elec-
tronic Control Modules section of the service manual
for heated seat module information.
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 andseat back cushions and cannot be removed from the
cushions, once installed at the factory.
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.
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 fuse #29 in the Junction Block (JB)
when the ignition switch is in the ªONº position. The
heated seat switches receive battery current through
fuse #25 in the Junction Block also, when the igni-
tion switch is in the ªONº 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. If the ignition switch is
turned to the Off position while a heated seat is
turned ON, the heated seat will remain Off after the
ignition switch is turned back ªONº until a heated
seat switch is depressed again.
8G - 10 HEATED SEAT SYSTEMKJ

OPERATION
There are three positions that can be selected with
each of the heated seat switches: Off, Low, and High.
When the front of the switch rocker is fully
depressed, the High position is selected and the high
position LED indicator illuminates. When the rear of
the switch rocker is fully depressed, the Low position
is selected and the low position LED indicator illumi-
nates. When the switch rocker is depressed a second
time in either direction, Off is selected and both LED
indicators are extinguished.
Both switches provide separate resistor multi-
plexed hard wire inputs to the Heated Seat Module
to indicate the selected switch position. The heated
seat module monitors the switch inputs and responds
to the heated seat switch status messages by control-
ling the output to the seat heater elements of the
selected seat. The Low heat position set point is
about 36É C (97É F), and the High heat position set
point is about 41É C (105É F).
DIAGNOSIS AND TESTING - HEATED SEAT
SWITCH
If a heated seat fails to heat and one or both of the
indicator lamps on a heated seat switch flash, refer
toHeated Seat System Diagnosis and Testingin
this section for flashing LED failure identification.
Refer toWiring Diagramsfor complete heated seat
system wiring diagrams.
(1) If the problem being diagnosed involves a
heated seat switch indicator lamp that remains illu-
minated after the heated seat has been turned Off,refer toDiagnosis and Testing the Heated Seat
Modulein the Electronic Control Modules section for
heated seat module diagnosis and testing procedures.
If not, go to Step 2
(2) Remove the heated seat switch (Refer to 8 -
ELECTRICAL/HEATED SEATS/DRIVER HEATED
SEAT SWITCH - REMOVAL). Check for continuity
between the ground circuit cavity #5 of the heated
seat switch connector and a good ground. There
should be continuity. If OK, go to Step 3. If not OK,
repair the open ground circuit as required.
(3) Turn the ignition switch to the ON position.
Check for battery voltage at the fused ignition switch
output circuit cavity #1 of the heated seat switch con-
nector. If OK, go to Step 4. If not OK, repair the open
fused ignition switch output circuit as required.
(4) Check the continuity between pin #1 and pin
#3 of the heated seat switch (Fig. 2). If the readings
do not correspond to those in the Heated Seat Switch
Continuity table below, replace the heated seat
switch. If OK, and the heated seat system is still not
operating properly refer toDiagnosis and Testing
the Heated Seat Module.
NOTE: ANY RESISTANCE VALUES (OHMSV) GIVEN
IN THE FOLLOWING TEXT ARE SUPPLIED USING
THE AUTOMATIC RANGE GENERATED BY A
FLUKETAUTOMOTIVE METER. IF ANOTHER TYPE
OF MEASURING DEVICE IS USED, THE VALUES
GENERATED MAY NOT BE THE SAME AS THE
RESULTS SHOWN HERE, OR MAY HAVE TO BE
CONVERTED TO THE RANGE USED HERE.
Fig. 1 KJ POWER / HEATED SEAT
Fig. 2 Heated Seat Switches
8G - 12 HEATED SEAT SYSTEMKJ
DRIVER SEAT HEATER SWITCH (Continued)

HEATED SEAT SWITCH CONTINUITY
CONTINUITY
BETWEENSWITCH
POSITIONOHMS
READING +/±
10%
PIN 1 AND 3 OFF 2.2 K (2200)
OHMS
PIN 1 AND 3 LO .415 K (415)
OHMS
PIN 1 AND 3 HI 33 OHMS
REMOVAL
(1) Disconnect and isolate the negative battery
cable.
(2) Remove the appropriate seat cushion side
shield (Refer to 23 - BODY/SEATS/SEAT CUSHION
SIDE COVERS - REMOVAL).
(3) Disconnect the heated seat switch electrical
connector. Depress the locking tab and pull straight
apart.
(4) Working from the underside of the switch, gen-
tly rock the switch back and forth out of its mounting
location.
INSTALLATION
(1) Gently rock the switch back and forth in to its
mounting location.
(2) Connect the heated seat switch electrical con-
nector.
(3) Install the appropriate seat cushion side shield.
Refer to the Body section of the service manual for
the procedure.
(4) Connect the negative battery cable.
HEATED SEAT ELEMENT
DESCRIPTION
The heated seat system includes four seat heating
elements. Two are located in each front seat, one for
the seat cushion and the other for the seat back. All
models use two resistor wire heating elements for
each seat that are connected in series with the
Heated Seat Module (HSM). The temperature sensor
is a Negative Temperature Coefficient (NTC) ther-
mistor. One temperature sensor is used for each seat,
and it is located on the seat cushion heating element
for all models.
The seat heating elements are permanently
attached to the seat cushions. The heated seat ele-
ments and the temperature sensor cannot be
adjusted or repaired and, if faulty or damaged, the
seat cushions must be replaced. Refer to the Body
section for the seat cushion service procedures.
OPERATION
The heated seat elements resist the flow of electrical
current. When battery current is passed through the
elements, the energy lost by the resistance of the ele-
ments to the current flow is released in the form of
heat. When the temperature of the seat cushion cover
rises, the resistance of the sensor decreases. The Heated
Seat Module supplies a five-volt current to one side of
each sensor, and monitors the voltage drop through the
sensor on a return circuit. The Heated Seat Module
uses this temperature sensor input to monitor the tem-
perature of the seat, and regulates the current flow to
the seat heating elements accordingly.
DIAGNOSIS AND TESTING - HEATED SEAT
ELEMENT
SEAT CUSHION ELEMENT
(1) Disconnect and isolate the battery negative
cable. Disconnect the green heated seat cushion ele-
ment wire harness connector from the power seat
wire harness. The power seat wire harness connec-
tors for the seat cushion heating elements are
secured to a bracket located under the seat cushion
frame. Refer toWiringfor connector pin information.
(2) Check for continuity between the two heated
seat element circuit cavities. There should be conti-
nuity. If OK, the elements within the seat assembly
test OK, go to Step 3. If not OK, replace the faulty
seat heating element and cushion assembly.
(3) Test the seat wire harness between the heated
seat module connector and the heated seat wire har-
ness element connector for a shorted or open circuit.
If OK, element is OK, proceed with testing the
heated seat sensor and module. If not OK, repair the
shorted or open seat wire harness as required.
SEAT BACK ELEMENT
(1) Disconnect and isolate the battery negative
cable. Disconnect the green heated seat back element
wire harness connector from the power seat wire har-
ness. The power seat wire harness connectors for the
seat cushion heating elements are secured to a
bracket located under the seat cushion frame. Refer
toWiringfor connector pin information.
(2) Check for continuity between the two heated
seat element circuit cavities. There should be conti-
nuity. If OK, the elements within the seat assembly
test OK, go to Step 3. If not OK, replace the faulty
seat heating element and cushion assembly.
(3) Test the seat wire harness between the heated
seat module connector and the heated seat wire har-
ness element connector for a shorted or open circuit.
If OK, element is OK, proceed with testing the
heated seat sensor and module. If not OK, repair the
shorted or open seat wire harness as required.
KJHEATED SEAT SYSTEM 8G - 13
DRIVER SEAT HEATER SWITCH (Continued)

(2) Remove the heated seat switch (Refer to 8 -
ELECTRICAL/HEATED SEATS/DRIVER HEATED
SEAT SWITCH - REMOVAL). Check for continuity
between the ground circuit cavity #5 of the heated
seat switch connector and a good ground. There
should be continuity. If OK, go to Step 3. If not OK,
repair the open ground circuit as required.
(3) Turn the ignition switch to the ON position.
Check for battery voltage at the fused ignition switch
output circuit cavity #1 of the heated seat switch con-
nector. If OK, go to Step 4. If not OK, repair the open
fused ignition switch output circuit as required.
(4) Check the continuity between pin #1 and pin
#3 of the heated seat switch (Fig. 4). If the readings
do not correspond to those in the Heated Seat Switch
Continuity table below, replace the heated seat
switch. If OK, and the heated seat system is still not
operating properly refer toDiagnosis and Testing
the Heated Seat Module.NOTE: ANY RESISTANCE VALUES (OHMSV) GIVEN
IN THE FOLLOWING TEXT ARE SUPPLIED USING
THE AUTOMATIC RANGE GENERATED BY A
FLUKETAUTOMOTIVE METER. IF ANOTHER TYPE
OF MEASURING DEVICE IS USED, THE VALUES
GENERATED MAY NOT BE THE SAME AS THE
RESULTS SHOWN HERE, OR MAY HAVE TO BE
CONVERTED TO THE RANGE USED HERE.
HEATED SEAT SWITCH CONTINUITY
CONTINUITY
BETWEENSWITCH
POSITIONOHMS
READING +/±
10%
PIN 1 AND 3 OFF 2.2 K (2200)
OHMS
PIN 1 AND 3 LO .415 K (415)
OHMS
PIN 1 AND 3 HI 33 OHMS
REMOVAL
(1) Disconnect and isolate the negative battery
cable.
(2) Remove the appropriate seat cushion side
shield (Refer to 23 - BODY/SEATS/SEAT CUSHION
SIDE COVERS - REMOVAL).
(3) Disconnect the heated seat switch electrical
connector. Depress the locking tab and pull straight
apart.
(4) Working from the underside of the switch, gen-
tly rock the switch back and forth out of its mounting
location.
INSTALLATION
(1) Gently rock the switch back and forth in to its
mounting location.
(2) Connect the heated seat switch electrical con-
nector.
(3) Install the appropriate seat cushion side shield.
Refer to the Body section of the service manual for
the procedure.
(4) Connect the negative battery cable.
Fig. 4 Heated Seat Switches
KJHEATED SEAT SYSTEM 8G - 15
PASSENGER SEAT HEATER SWITCH (Continued)

REMOVAL
(1)Disconnect and isolate the battery negative cable.
(2) Disconnect the electrical harness connector
from the horns.
(3) Remove the mounting bolt (Fig. 2).
(4) Remove the horns.
INSTALLATION
(1) Install the horns.
(2) Install the mounting bolt. Tighten bolt to 25
N´m (19 lb. ft.).
(3) Connect the electrical harness connector to the
horns
(4) Connect the battery negative cable.
HORN RELAY
DIAGNOSIS AND TESTING - HORN RELAY
(1) Remove horn relay (Refer to 8 - ELECTRICAL/
HORN/HORN RELAY - REMOVAL).
(2) Using ohmmeter, test between relay connector
terminals 85 to 86 for 75   8 ohms resistance. If
resistance not OK, replace relay (Fig. 3).
(3) Test for continuity between ground and termi-
nal 85 of horn relay.
(a) When the horn switch is not depressed, no
continuity should be present.
(b) Continuity to ground when horn switch is
depressed.
(c) If continuity is not correct replace horn
switch or wiring as necessary, refer to the appro-
priate wiring information. The wiring information
includes wiring diagrams, proper wire and connec-
tor repair procedures, details of wire harness rout-ing and retention, connector pin-out information
and location views for the various wire harness
connectors, splices and grounds.
(4) Using voltmeter, test voltage at:
(a) Terminals 30 and 86 of the horn relay to
body ground.
(b) If NO voltage check fuse 3 of the Junction
Block (JB).
(c) If incorrect voltage, repair as necessary. 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.
(5) Insert a jumper wire between terminal 30 and
87 of the Junction Block (JB).
(a) If horn sounds replace relay.
(b) If the horn does not sound, install horn relay
and test horn (Refer to 8 - ELECTRICAL/HORN/
HORN - DIAGNOSIS AND TESTING).
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the instrument panel end cap.
(3) Locate and pull the horn relay from the Junc-
tion Block (JB).
INSTALLATION
(1) Locate proper connector, and press relay into
position.
(2) Install instrument panel end cap.
(3) Connect battery negative cable.
Fig. 2 HORN MOUNTING
1 - POWER DISTRIBUTION CENTER
2 - LOW NOTE HORN
3 - HIGH NOTE HORN
Fig. 3 Horn Relay
30 - COMMON FEED
85 - COIL GROUND
86 - COIL BATTERY
87 - NORMALLY OPEN
87A - NORMALLY CLOSED
KJHORN 8H - 3
HORN (Continued)

HORN SWITCH
DESCRIPTION
The horn switch is molded into the driver airbag
assembly. The horn switch can not be serviced sepa-
rately. For service procedures, (Refer to 8 - ELEC-
TRICAL/RESTRAINTS/DRIVER AIRBAG -
REMOVAL).
DIAGNOSIS AND TESTING - HORN SWITCH
For complete circuit diagrams, refer to the appro-
priate 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 connec-
tors, splices and grounds.
WARNING: DISABLE THE AIRBAG SYSTEM
BEFORE ATTEMPTING ANY STEERING WHEEL,
STEERING COLUMN, SEAT BELT TENSIONER, SIDE
AIRBAG, 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.
(2) Remove the steering column opening cover.
(3) Check for continuity between the metal steer-
ing column jacket and a good ground. There should
be continuity. If OK, go to Step 4. If not OK,(Refer to
19 - STEERING/COLUMN - INSTALLATION) for
proper installation of the steering column.
(4) Remove the driver side airbag module from the
steering wheel (Refer to 8 - ELECTRICAL/RE-
STRAINTS/DRIVER AIRBAG - REMOVAL). Discon-
nect the horn switch wire harness connectors from
the driver side airbag module (Fig. 4).
(5) Remove the horn relay from the Junction Block
(JB). Check for continuity between the steering col-umn half of the horn switch feed wire harness con-
nector and a good ground. There should be no
continuity. If OK, go to Step 6. If not OK, repair the
shorted horn relay control circuit to the horn relay in
the Junction Block as required.
(6) Check for continuity between the steering col-
umn half of the horn switch feed wire harness con-
nector and the horn relay control circuit cavity for
the horn relay in the Junction Block. There should be
continuity. If OK, go to Step 7. If not OK, repair the
open horn relay control circuit to the horn relay in
the Junction Block as required.
(7) Check for continuity between the horn switch
feed wire and the horn switch ground wire on the
driver side airbag module. There should be no conti-
nuity. If OK, go to Step 8. If not OK, replace the
faulty horn switch.
(8) Depress the center of the driver side airbag
module trim cover and check for continuity between
the horn switch feed wire and the horn switch
ground wire on the driver side airbag module. There
should now be continuity. If not OK, replace the
faulty horn switch (Refer to 8 - ELECTRICAL/RE-
STRAINTS/DRIVER AIRBAG - REMOVAL).
Fig. 4 Driver Airbag Housing
1 - HOUSING
2 - HORN SWITCH GROUND WIRE
3 - HORN SWITCH FEED WIRE
4 - INFLATOR
5 - TRIM COVER
8H - 4 HORNKJ

IGNITION CONTROL
TABLE OF CONTENTS
page page
IGNITION CONTROL
DESCRIPTION..........................1
OPERATION............................1
SPECIFICATIONS
SPECIFICATIONS - IGNITION TIMING.......2
ENGINE FIRING ORDER - 2.4L 4-CYLINDER . 2
ENGINE FIRING ORDER - 3.7L V-6.........2
IGNITION COIL RESISTANCE - 2.4L........2
IGNITION COIL RESISTANCE - 3.7L V-6.....3
SPARK PLUGS........................3
SPARK PLUG CABLE RESISTANCE - 2.4L . . . 3
TORQUE - IGNITION SYSTEM............3
AUTO SHUT DOWN RELAY
DESCRIPTION - PCM OUTPUT.............4
OPERATION
OPERATION - ASD SENSE - PCM INPUT....4
OPERATION - PCM OUTPUT.............4
DIAGNOSIS AND TESTING - ASD AND FUEL
PUMP RELAYS........................4
REMOVAL.............................5
INSTALLATION..........................5
CAMSHAFT POSITION SENSOR
DESCRIPTION
DESCRIPTION - 2.4L....................5
DESCRIPTION-3.7L.....................6
OPERATION
OPERATION - 2.4L.....................6OPERATION - 3.7L.....................6
REMOVAL.............................7
INSTALLATION..........................8
IGNITION COIL
DESCRIPTION..........................9
OPERATION............................9
REMOVAL.............................10
INSTALLATION.........................10
KNOCK SENSOR
DESCRIPTION.........................11
OPERATION...........................11
REMOVAL.............................12
INSTALLATION.........................12
SPARK PLUG
DESCRIPTION.........................12
OPERATION...........................12
DIAGNOSIS AND TESTING - SPARK PLUG
CONDITIONS.........................13
REMOVAL.............................15
CLEANING SPARK PLUGS................15
INSTALLATION.........................15
IGNITION COIL CAPACITOR
DESCRIPTION.........................16
OPERATION...........................16
REMOVAL.............................16
INSTALLATION.........................16
IGNITION CONTROL
DESCRIPTION
The ignition system consists of:
²Spark Plugs
²Ignition Coil(s)
²Powertrain Control Module (PCM)
²Crankshaft Position Sensor
²2 Knock Sensors (3.7L only)
²Camshaft Position Sensor
²The MAP, TPS, IAC and ECT also have an effect
on the control of the ignition system.
OPERATION
2.4L
A common ignition coil divided into 2 halves is
used. Secondary, high-tension spark plug cables are
also used. One half of the coil fires two spark plugs
simultaneously (one plug is the cylinder under com-pression, and the other plug is the cylinder on the
exhaust stroke). Coil half number one fires cylinders
1 and 4. Coil half number two fires cylinders 2 and 3.
The PCM determines which of the coils to charge and
fire at the correct time.
The Auto Shutdown (ASD) relay provides battery
voltage to the ignition coil. The PCM provides a
ground contact (circuit) for energizing the coil. When
the PCM breaks the contact, the energy in the coil
primary transfers to the secondary causing a spark.
The PCM will de-energize the ASD relay if it does
not receive inputs from either the crankshaft or cam-
shaft position sensors.
A distributor is not used with the 2.4L engine.
3.7L
The 3.7L V6 engine uses a separate ignition coil for
each cylinder. The one-piece coil bolts directly to the
cylinder head. Rubber boots seal the secondary ter-
minal ends of the coils to the top of all 6 spark plugs.
A separate electrical connector is used for each coil.
KJIGNITION CONTROL 8I - 1

(4) Connect the ohmmeter between terminals 87
and 30. The ohmmeter should not show continuity at
this time.
(5) Connect one end of a jumper wire (16 gauge or
smaller) to relay terminal 85. Connect the other end
of the jumper wire to the ground side of a 12 volt
power source.
(6) Connect one end of another jumper wire (16
gauge or smaller) to the power side of the 12 volt
power source.Do not attach the other end of the
jumper wire to the relay at this time.
WARNING: DO NOT ALLOW OHMMETER TO CON-
TACT TERMINALS 85 OR 86 DURING THIS TEST.
DAMAGE TO OHMMETER MAY RESULT.
(7) Attach the other end of the jumper wire to
relay terminal 86. This activates the relay. The ohm-
meter should now show continuity between relay ter-
minals 87 and 30. The ohmmeter should not show
continuity between relay terminals 87A and 30.
(8) Disconnect jumper wires.
(9) Replace the relay if it did not pass the continu-
ity and resistance tests. If the relay passed the tests,
it operates properly. Check the remainder of the ASD
and fuel pump relay circuits. Refer to 8, Wiring Dia-
grams.
REMOVAL
The ASD relay is located in the Power Distribution
Center (PDC) (Fig. 4). Refer to label on PDC cover
for relay location.(1) Remove PDC cover.
(2) Remove relay from PDC.
(3) Check condition of relay terminals and PDC
connector terminals for damage or corrosion. Repair
if necessary before installing relay.
(4) Check for pin height (pin height should be the
same for all terminals within the PDC connector).
Repair if necessary before installing relay.
INSTALLATION
The ASD relay is located in the Power Distribution
Center (PDC). Refer to label on PDC cover for relay
location.
(1) Install relay to PDC.
(2) Install cover to PDC.
CAMSHAFT POSITION
SENSOR
DESCRIPTION
DESCRIPTION - 2.4L
The Camshaft Position Sensor (CMP) on the 2.4L
4±cylinder engine is bolted to the right-front side of
the cylinder head (Fig. 5).
Fig. 4 POWER DISTRIBUTION CENTER (PDC)
1 - BATTERY
2 - PDC
3 - PDC COVER
Fig. 5 CMP LOCATION - 2.4L
1 - CMP SENSOR
2 - ELECTRICAL CONNECTOR
3-
4 - SLOTTED HOLES
5 - MOUNTING BOLTS (2)
KJIGNITION CONTROL 8I - 5
AUTO SHUT DOWN RELAY (Continued)