coil JEEP GRAND CHEROKEE 2003 WJ / 2.G Owner's Manual

OPERATION
These starter motors are equipped with a plane-
tary gear reduction (intermediate transmission) sys-
tem. The planetary gear reduction system consists of
a gear that is integral to the output end of the elec-
tric motor armature shaft that is in continual
engagement with a larger gear that is splined to the
input end of the starter pinion gear shaft. This fea-
ture makes it possible to reduce the dimensions of
the starter. At the same time, it allows higher arma-
ture rotational speed and delivers increased torque
through the starter pinion gear to the starter ring
gear.
The starter motors for both engines are activated
by an integral heavy duty starter solenoid switch
mounted to the overrunning clutch housing. This
electromechanical switch connects and disconnects
the feed of battery voltage to the starter motor and
actuates a shift fork that engages and disengages the
starter pinion gear with the starter ring gear.
Both starter motors use an overrunning clutch and
starter pinion gear unit to engage and drive a starter
ring gear that is integral to the torque converter
drive plate mounted on the rear crankshaft flange.
DIAGNOSIS AND TESTING - STARTER MOTOR
Correct starter motor operation can be confirmed
by performing the following free running bench test.
This test can only be performed with the starter
motor removed from the vehicle. Refer toStarting
Systemin the Specifications section of this group for
the starter motor specifications.
(1) Remove the starter motor from the vehicle.
Refer toStarter Motorin the Removal and Instal-
lation section of this group for the procedures.
(2) Mount the starter motor securely in a soft-
jawed bench vise. The vise jaws should be clamped
on the mounting flange of the starter motor. Never
clamp on the starter motor by the field frame.
(3) Connect a suitable volt-ampere tester and a
12-volt battery to the starter motor in series, and set
the ammeter to the 100 ampere scale. See the
instructions provided by the manufacturer of the
volt-ampere tester being used.
(4) Install a jumper wire from the solenoid termi-
nal to the solenoid battery terminal. The starter
motor should operate. If the starter motor fails to
operate, replace the faulty starter motor assembly.
(5) Adjust the carbon pile load of the tester to
obtain the free running test voltage. Refer toStart-
ing Systemin the Specifications section of this
group for the starter motor free running test voltage
specifications.
(6) Note the reading on the ammeter and compare
this reading to the free running test maximum
amperage draw. Refer toStarting Systemin theSpecifications section of this group for the starter
motor free running test maximum amperage draw
specifications.
(7) If the ammeter reading exceeds the maximum
amperage draw specification, replace the faulty
starter motor assembly.
STARTER SOLENOID
This test can only be performed with the starter
motor removed from the vehicle.
(1) Remove the starter motor from the vehicle.
Refer toStarter Motorin the Removal and Instal-
lation section of this group for the procedures.
(2) Disconnect the wire from the solenoid field coil
terminal.
(3) Check for continuity between the solenoid ter-
minal and the solenoid field coil terminal with a con-
tinuity tester (Fig. 7). There should be continuity. If
OK, go to Step 4. If not OK, replace the faulty starter
motor assembly.
(4) Check for continuity between the solenoid ter-
minal and the solenoid case (Fig. 8). There should be
continuity. If not OK, replace the faulty starter motor
assembly.
Fig. 7 Continuity Test Between Solenoid Terminal
and Field Coil Terminal - Typical
1 - SOLENOID
2 - SOLENOID TERMINAL
3 - OHMMETER
4 - FIELD COIL TERMINAL
Fig. 8 Continuity Test Between Solenoid Terminal
1 - SOLENOID
2 - SOLENOID TERMINAL
3 - OHMMETER
8F - 36 STARTINGWJ
STARTER MOTOR (Continued)

(8) Remove the starter motor from the engine com-
partment.
INSTALLATION
(1) Position the starter motor in the engine com-
partment.
(2) Reconnect the solenoid terminal wire harness
connector to the connector receptacle on the starter
solenoid. Always support the starter motor during
this process, do not let the starter motor hang from
the wire harness.
(3) Install the battery cable eyelet onto the sole-
noid battery terminal. Always support the starter
motor during this process, do not let the starter
motor hang from the wire harness.
(4) Install and tighten the nut that secures the
battery cable eyelet to the solenoid battery terminal.
Tighten the nut to 11.3 N´m (100 in. lbs.). Always
support the starter motor during this process, do not
let the starter motor hang from the wire harness.
(5) Position the starter motor to the front of the
automatic transmission torque converter housing and
loosely install both the upper and lower mounting
screws.
(6) Tighten the lower (forward facing) starter
motor mounting screw. On 4.0L engines, tighten the
screw to 41 N´m (30 ft. lbs.). On 4.7L engines, tighten
the screw to 54 N´m (40 ft. lbs.).(7) Tighten the upper (rearward facing) starter
mounting screw. Tighten the screw to 54 N´m (40 ft.
lbs.).
(8) Lower the vehicle.
(9) Reconnect the battery negative cable.
STARTER MOTOR RELAY
DESCRIPTION
The starter relay is an electromechanical device
that switches battery current to the pull-in coil of the
starter solenoid when the ignition switch is turned to
the Start position. The starter relay is located in the
Power Distribution Center (PDC), in the engine com-
partment. See the fuse and relay layout label affixed
to the inside surface of the PDC cover for starter
relay identification and location.
The starter relay is a International Standards
Organization (ISO) micro-relay. Relays conforming to
the ISO specifications have common physical dimen-
sions, current capacities, terminal patterns, and ter-
minal functions. The ISO micro-relay terminal
functions are the same as a conventional ISO relay.
However, the ISO micro-relay terminal pattern (or
footprint) is different, the current capacity is lower,
and the physical dimensions are smaller than those
of the conventional ISO relay.
The starter relay cannot be repaired or adjusted
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 or diode is con-
nected in parallel with the electromagnetic coil in the
relay, and helps to dissipate voltage spikes that are
produced when the coil is de-energized.
DIAGNOSIS AND TESTING - STARTER RELAY
The starter relay (Fig. 13) is located in the Power
Distribution Center (PDC), in the engine compart-
ment. Refer to the fuse and relay layout label affixed
to the underside of the PDC cover for starter relay
identification and location. For complete circuit dia-
grams, refer toStarting Systemin the Contents of
Group 8W - Wiring Diagrams.
Fig. 12 Starter Wire Harness Remove/Install - 4.7L
Engine
1 - SOLENOID BATTERY TERMINAL EYELET
2 - NUT
3 - SOLENOID TERMINAL CONNECTOR
4 - BATTERY STARTER AND GENERATOR WIRE HARNESS
5 - RETAINERS
8F - 38 STARTINGWJ
STARTER MOTOR (Continued)

(1) Remove the starter relay from the PDC. Refer
toStarter Relayin the Removal and Installation
section of this group for the procedures.
(2) A relay in the de-energized position should
have continuity between terminals 87A and 30, and
no continuity between terminals 87 and 30. If OK, go
to Step 3. If not OK, replace the faulty relay.
(3) Resistance between terminals 85 and 86 (elec-
tromagnet) should be 75   5 ohms. If OK, go to Step
4. If not OK, replace the faulty relay.
(4) Connect a battery to terminals 85 and 86.
There should now be continuity between terminals
30 and 87, and no continuity between terminals 87A
and 30. If OK, perform the Relay Circuit Test that
follows. If not OK, replace the faulty relay.
RELAY CIRCUIT TEST
(1) The relay common feed terminal cavity (30) is
connected to battery voltage and should be hot at all
times. If OK, go to Step 2. If not OK, repair the open
circuit to the fuse in the PDC as required.
(2) The relay normally closed terminal (87A) is
connected to terminal 30 in the de-energized position,
but is not used for this application. Go to Step 3.
(3) The relay normally open terminal (87) is con-
nected to the common feed terminal (30) in the ener-
gized position. This terminal supplies battery voltage
to the starter solenoid field coils. There should be
continuity between the cavity for relay terminal 87
and the starter solenoid terminal at all times. If OK,
go to Step 4. If not OK, repair the open circuit to the
starter solenoid as required.
(4) The coil battery terminal (86) is connected to
the electromagnet in the relay. It is energized when
the ignition switch is held in the Start position.
Check for battery voltage at the cavity for relay ter-
minal 86 with the ignition switch in the Start posi-tion, and no voltage when the ignition switch is
released to the On position. If OK, go to Step 5. If
not OK, check for an open or short circuit to the igni-
tion switch and repair, if required. If the circuit to
the ignition switch is OK, refer toIgnition Switch
and Key Lock Cylinderin the Diagnosis and Test-
ing section of Group 8D - Ignition System for testing
of the ignition switch.
(5) The coil ground terminal (85) is connected to
the electromagnet in the relay. It is grounded
through the park/neutral position switch only when
the gearshift selector lever is in the Park or Neutral
positions. Check for continuity to ground at the cav-
ity for relay terminal 85. If not OK, check for an
open or short circuit to the park/neutral position
switch and repair, if required. If the circuit to the
park/neutral position switch is OK, refer toPark/
Neutral Position Switchin the Diagnosis and
Testing section of Group 21 - Transmission for testing
of the park/neutral position switch.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the cover from the Power Distribution
Center (PDC) (Fig. 14) .
Fig. 13 Starter Relay
30 - COMMON FEED
85 - COIL GROUND
86 - COIL BATTERY
87 - NORMALLY OPEN
87A - NORMALLY CLOSED
Fig. 14 Power Distribution Center
1 - RIGHT FENDER
2 - BATTERY
3 - POWER DISTRIBUTION CENTER
4 - COVER
WJSTARTING 8F - 39
STARTER MOTOR RELAY (Continued)

(1) Confirm that the ignition switch is in the On
position.
(2) Ensure that the rear glass heating grid feed
and ground terminals are connected to the glass.
Confirm that the ground wire has continuity to
ground.
(3) Check the fused B(+) fuse in the Power Distri-
bution Center (PDC). The fuse must be tight in its
receptacles and all electrical connections must be
secure.
When the above steps have been completed and the
rear glass heating grid is still inoperative, one or
more of the following is faulty:
²Rear window defogger switch
²Rear window defogger relay
²Body Control Module (BCM)
²Rear window grid lines (all grid lines would
have to be broken or one of the feed wires discon-
nected for the entire system to be inoperative).
When the above steps have been completed and the
heated mirror glass heating grid is still inoperative,
one or more of the following is faulty:
²Body Control Module (BCM)
²Programmable Communications Interface (PCI)
data bus
²Driver Door Module (DDM) or Passenger Door
Module (PDM)
²Outside rear view mirror heating grids.
If turning the rear window defogger system on pro-
duces a severe voltmeter deflection, check for a short
circuit between the rear window defogger relay out-
put and the rear glass heating grid.
REAR WINDOW DEFOGGER
GRID
DESCRIPTION
The electrically heated rear window glass is stan-
dard equipment on this model. The liftgate flip-up
glass has two electrically conductive vertical bus bars
and a series of horizontal grid lines made of a silver-
ceramic material, which is baked on and bonded to
the inside surface of the glass. These grid lines and
the bus bars comprise a parallel electrical circuit. A
spade type terminal near the top of each bus bar
accept the connectors from the two coiled liftgate
wire harness take outs.
The grid lines and bus bars are highly resistant to
abrasion. However, it is possible for an open circuit
to occur in an individual grid line, resulting in no
current flow through the line. The grid lines can be
damaged or scraped off with sharp instruments. Care
should be taken when cleaning the glass or removing
foreign materials, decals, or stickers from the glass.Normal glass cleaning solvents or hot water used
with rags or toweling is recommended.
A repair kit is available to repair the grid lines and
bus bars, or to reinstall the heated glass terminals.
(Refer to 8 - ELECTRICAL/HEATED GLASS/REAR
WINDOW DEFOGGER GRID - STANDARD PROCE-
DURE)
OPERATION
The rear glass heating grid is energized and de-en-
ergized by the rear window defogger relay. The Body
Control Module (BCM) monitors the rear window
defogger switch. When the BCM receives an input
from the switch, it energizes or de-energizes the rear
window defogger relay through a hard wired control
output. The rear defogger relay switches fused bat-
tery current to the rear window grid lines through
the bus bars. The grid lines heat the rear window
glass to clear the surface of ice, snow or fog. Protec-
tion for the rear glass heating grid circuit is provided
by a fuse in the Power Distribution Center (PDC).
DIAGNOSIS AND TESTING - REAR WINDOW
DEFOGGER GRID
For complete circuit diagrams, (Refer to Appropri-
ate Wiring Information). To detect breaks in the rear
glass heating grid lines, the following procedure is
required:
(1) Turn the ignition switch to the On position.
Turn the rear window defogger system on. The rear
window defogger switch LED indicator should light.
If OK, go to Step 2. If not OK, (Refer to 8 - ELEC-
TRICAL/HEATED GLASS/REAR WINDOW DEFOG-
GER RELAY - DIAGNOSIS AND TESTING).
(2) Using a 12-volt DC voltmeter, contact the rear
glass heating grid vertical bus bar on the right side
of the vehicle with the negative lead. With the posi-
tive lead, contact the rear glass heating grid vertical
bus bar on the left side of the vehicle. The voltmeter
should read battery voltage. If OK, go to Step 3. If
not OK, repair the open rear window defogger relay
output circuit to the rear window defogger relay as
required.
(3) With the positive voltmeter lead still contacting
the rear glass heating grid vertical bus bar on the
left side of the vehicle, move the negative lead of the
voltmeter to a good body ground point. The voltage
reading should not change. If OK, go to Step 4. If not
OK, repair the ground circuit to ground as required.
(4) Connect the negative lead of the voltmeter to
the right side bus bar and touch each grid line at
midpoint C with the positive lead (Fig. 2). A reading
of approximately six volts indicates a line is good. A
reading of zero volts indicates a break in the grid
line between midpoint C and the left side rear glass
heating grid bus bar. A reading of ten to fourteen
WJHEATED GLASS 8G - 3
HEATED GLASS (Continued)

not attach the wire harness connectors until the cur-
ing process is complete.
(11) Check the operation of the rear glass heating
grid.
REAR WINDOW DEFOGGER
RELAY
DESCRIPTION
The rear window defogger relay is an electrome-
chanical device that switches fused battery current to
the rear glass heating grid and the Light-Emitting
Diode (LED) indicator of the rear window defogger
switch, when the Body Control Module (BCM) rear
window defogger timer and logic circuitry grounds
the relay coil. The rear window defogger relay is
located in the junction block, under the left end of
the instrument panel in the passenger compartment.
The rear window defogger relay is a International
Standards Organization (ISO) relay. Relays conform-
ing to the ISO specifications have common physical
dimensions, current capacities, terminal patterns,
and terminal functions.
The rear window defogger relay cannot be repaired
or adjusted 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 or diode is con-
nected in parallel with the electromagnetic coil in the
relay, and helps to dissipate voltage spikes that are
produced 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 rear window defogger relay (Fig. 4) is located
in the junction block, under the left end of the instru-
ment panel in the passenger compartment. Remove
the rear window 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
no continuity between terminals 87 and 30. If OK, go
to Step 2. If not OK, replace the faulty relay.
(2) Resistance between terminals 85 and 86 (elec-
tromagnet) should be 75   10 ohms. If OK, go to Step
3. If not OK, replace the faulty relay.
(3) Connect a battery to terminals 85 and 86.
There should now be continuity between terminals
30 and 87, and no continuity between terminals 87A
and 30. If OK, refer to theRelay Circuit Test.If
not OK, replace the faulty relay.
RELAY CIRCUIT TEST
(1) The relay common feed terminal cavity (30) is
connected to battery voltage and should be hot at all
times. If OK, go to Step 2. If not OK, repair the open
fused B(+) circuit to the Power Distribution Center
(PDC) fuse as required.
(2) The relay normally closed terminal (87A) is
connected to terminal 30 in the de-energized position,
but is not used for this application. Go to Step 3.
Fig. 4 REAR WINDOW DEFOGGER RELAY
TERMINAL LEGEND
NUMBER IDENTIFICATION
30 COMMON FEED
85 COIL GROUND
86 COIL BATTERY
87 NORMALLY OPEN
87A NORMALLY CLOSED
WJHEATED GLASS 8G - 5
REAR WINDOW DEFOGGER GRID (Continued)

(3) The relay normally open terminal (87) is con-
nected to the common feed terminal (30) in the ener-
gized position. This terminal supplies battery voltage
to the rear glass heating grid and to the fuse in the
junction block that feeds the rear window defogger
switch LED indicator. There should be continuity
between the cavity for relay terminal 87 and the rear
glass heating grid and the rear window defogger
switch LED indicator at all times. If OK, go to Step
4. If not OK, repair the open rear window defogger
relay output circuit 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 fused
B(+) circuit to the PDC fuse as required.
(5) The coil ground terminal (85) is connected to
the electromagnet in the relay. This terminal is pro-
vided with ground by the Body Control Module
(BCM) rear window defogger timer and logic circuitry
to energize the defogger relay. There should be conti-
nuity to the rear window defogger relay control cir-
cuit cavity of the 22-way instrument panel wire
harness connector for the BCM. If OK, use a DRB
scan tool and refer to the Appropriate Diagnostic
Information to test the BCM. If not OK, repair the
open rear window defogger relay control circuit as
required.
REMOVAL
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.
(2) Remove the steering column opening cover
from the instrument panel. Refer to Instrument
Panel System for the procedures.
(3) The rear window defogger relay is located on
the right side of the combination flasher in the junc-
tion block (Fig. 5).
(4) Remove the rear window defogger relay from
the junction block.
INSTALLATION
(1) Position the rear window defogger relay in the
proper receptacle in the junction block.
(2) Align the rear window defogger relay terminals
with the terminal cavities in the junction block recep-
tacle.
(3) Push in firmly on the rear window defogger
relay until the terminals are fully seated in the ter-
minal cavities in the junction block receptacle.
(4) Install the steering column opening cover onto
the instrument panel. Refer to Instrument Panel Sys-
tem for the procedures.
(5) Reconnect the battery negative cable.
REAR WINDOW DEFOGGER
SWITCH
DESCRIPTION
The rear window defogger switch is integral to the
a/c heater control, which is located in the instrument
panel center stack below the radio receiver. This
momentary switch provides a hard wired ground sig-
nal to the Body Control Module (BCM) each time it is
depressed. A Light Emitting Diode (LED) in the push
button for the rear window defogger switch illumi-
nates to indicate when the rear window defogger sys-
tem is turned on.
The rear window defogger switch and the rear win-
dow defogger switch LED indicator cannot be
Fig. 5 JUNCTION BLOCK
1 - COMBINATION FLASHER
2 - JUNCTION BLOCK
8G - 6 HEATED GLASSWJ
REAR WINDOW DEFOGGER RELAY (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
HORN SOUNDS
CONTINUOUSLY1. Faulty horn relay. 1. Refer to Horn Relay for the proper horn relay
diagnosis and testing procedures. Replace the
horn relay or repair the shorted horn relay control
circuit, if required.
2. Faulty horn switch. 2. Refer to Horn Switch for the proper horn switch
diagnosis and testing procedures. Replace the
horn switch or repair the shorted horn switch
circuit, if required.
HORN
DESCRIPTION
The dual electromagnetic diaphragm-type horns
are standard equipment on this model. Both horns
are secured to a mounting bracket. The mounting
bracket is secured with a screw to the back side of
the right extension of the radiator closure assembly,
just ahead of the right front wheel house and below
the front wheel house extension. The two horns are
connected in parallel. Each horn is grounded through
its wire harness connector and circuit to an eyelet
secured to the right inner fender shield near the bat-
tery, and receives battery feed through the closed
contacts of the horn relay.
The horns cannot be repaired or adjusted and, if
faulty or damaged, they must be individually
replaced.
OPERATION
Within the two halves of the molded plastic horn
housing are a flexible diaphragm, a plunger, an elec-
tromagnetic coil and a set of contact points. The dia-
phragm is secured in suspension around its
perimeter by the mating surfaces of the horn hous-
ing. The plunger is secured to the center of the dia-
phragm and extends into the center of the
electromagnet. The contact points control the current
flow through the electromagnet.
When the horn is energized, electrical current
flows through the closed contact points to the electro-
magnet. The resulting electromagnetic field draws
the plunger and diaphragm toward it until that
movement mechanically opens the contact points.
When the contact points open, the electromagnetic
field collapses allowing the plunger and diaphragm to
return to their relaxed positions and closing the con-
tact points again. This cycle continues repeating at a
very rapid rate producing the vibration and move-
ment of air that creates the sound that is directed
through the horn outlet.
DIAGNOSIS AND TESTING - HORN
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.
(1) Disconnect the wire harness connector(s) from
the horn connector receptacle(s). Measure the resis-
tance between the ground circuit cavity of the horn(s)
wire harness connector(s) and a good ground. There
should be no measurable resistance. If OK, go to Step
2. If not OK, repair the open ground circuit to ground
as required.
(2) Check for battery voltage at the horn relay out-
put circuit cavity of the horn(s) wire harness connec-
tor(s). There should be zero volts. If OK, go to Step 3.
If not OK, repair the shorted horn relay output cir-
cuit or replace the faulty horn relay as required.
(3) Depress the horn switch. There should now be
battery voltage at the horn relay output circuit cavity
of the horn(s) wire harness connector(s). If OK,
replace the faulty horns. If not OK, repair the open
horn relay output circuit to the horn relay as
required.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Raise and support the vehicle.
(3) Remove the lower front half of the inner liner
from the right front fender wheel house. (Refer to 23
- BODY/EXTERIOR/FRONT FENDER - REMOVAL).
(4) Reach through the front of the right front
fender wheel house opening to access and disconnect
the two right headlamp and dash wire harness con-
nectors from the horn connector receptacles (Fig. 1).
Be certain to disengage the connector lock tabs
before disconnecting them from the horn connector
receptacles.
(5) Remove the screw that secures the horn
mounting bracket to the right extension of the radi-
ator closure assembly.
WJHORN 8H - 3
HORN SYSTEM (Continued)

(6) Remove both horns and the mounting bracket
from the right extension of the radiator closure
assembly as a unit.
INSTALLATION
(1) Position both horns and the mounting bracket
onto the right extension of the radiator closure
assembly as a unit.
(2) Install and tighten the screw that secures the
horn mounting bracket to the right extension of the
radiator closure assembly. Tighten the screw to 11.3
N´m (100 in. lbs.).
(3) Reconnect the two right headlamp and dash
wire harness connectors to the horn connector recep-
tacles. Be certain to engage the connector lock tabs
after reconnecting them to the horn connector recep-
tacles.
(4) Install the lower front half of the inner liner to
the right front fender wheel house. (Refer to 23 -
BODY/EXTERIOR/FRONT FENDER - INSTALLA-
TION) for the procedure.
(5) Lower the vehicle.
(6) Reconnect the battery negative cable.
HORN RELAY
DESCRIPTION
The horn relay is a electromechanical device that
switches battery current to the horn when the horn
switch grounds the relay coil. The horn relay is
located in the Power Distribution Center (PDC) inthe engine compartment. If a problem is encountered
with a continuously sounding horn, it can usually be
quickly resolved by removing the horn relay from the
PDC until further diagnosis is completed. See the
fuse and relay layout label affixed to the inside sur-
face of the PDC cover for horn relay identification
and location.
The horn relay is a International Standards Orga-
nization (ISO) micro-relay. Relays conforming to the
ISO specifications have common physical dimensions,
current capacities, terminal patterns, and terminal
functions. The ISO micro-relay terminal functions
are the same as a conventional ISO relay. However,
the ISO micro-relay terminal pattern (or footprint) is
different, the current capacity is lower, and the phys-
ical dimensions are smaller than those of the conven-
tional ISO relay.
The horn relay cannot be repaired or adjusted 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 or diode is con-
nected in parallel with the electromagnetic coil in the
relay, and helps to dissipate voltage spikes that are
produced when the coil is de-energized.
DIAGNOSIS AND TESTING - HORN RELAY
The horn relay (Fig. 2) is located in the Power Dis-
tribution Center (PDC) between the battery and the
right inner fender shield on the passenger side of the
engine compartment. If a problem is encountered
with a continuously sounding horn, it can usually be
quickly resolved by removing the horn relay from the
PDC until further diagnosis is completed. See the
fuse and relay layout label affixed to the inside sur-
face of the PDC cover for horn relay identification
and location. For complete circuit diagrams, refer to
the appropriate wiring information. The wiring infor-
mation includes wiring diagrams, proper wire and
connector repair procedures, details of wire harness
routing and retention, connector pin-out information
and location views for the various wire harness con-
nectors, splices and grounds.
Fig. 1 Horns Remove/Install
1 - RADIATOR CLOSURE ASSEMBLY
2 - HORNS AND MOUNTING BRACKET
3 - RIGHT HEADLAMP AND DASH WIRE HARNESS
CONNECTORS
8H - 4 HORNWJ
HORN (Continued)

WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, REFER TO ELECTRICAL, RESTRAINTS
BEFORE ATTEMPTING ANY STEERING WHEEL,
STEERING COLUMN, OR INSTRUMENT PANEL
COMPONENT DIAGNOSIS OR SERVICE. FAILURE
TO TAKE THE PROPER PRECAUTIONS COULD
RESULT IN ACCIDENTAL AIRBAG DEPLOYMENT
AND POSSIBLE PERSONAL INJURY.
(1) Remove the horn relay from the PDC. (Refer to
8 - ELECTRICAL/HORN/HORN RELAY -
REMOVAL) for the procedures.
(2) A relay in the de-energized position should
have continuity between terminals 87A and 30, and
no continuity between terminals 87 and 30. If OK, go
to Step 3. If not OK, replace the faulty relay.
(3) Resistance between terminals 85 and 86 (elec-
tromagnet) should be 75   5 ohms. If OK, go to Step
4. If not OK, replace the faulty relay.
(4) Connect a battery to terminals 85 and 86.
There should now be continuity between terminals
30 and 87, and no continuity between terminals 87A
and 30. If OK, perform the Relay Circuit Test that
follows. If not OK, replace the faulty relay.
RELAY CIRCUIT TEST
(1) The relay common feed terminal cavity (30) is
connected to battery voltage and should be hot at all
times. If OK, go to Step 2. If not OK, repair the open
circuit to the fuse in the PDC as required.
(2) The relay normally closed terminal (87A) is
connected to terminal 30 in the de-energized position,
but is not used for this application. Go to Step 3.(3) The relay normally open terminal (87) is con-
nected to the common feed terminal (30) in the ener-
gized position. This terminal supplies battery voltage
to the horn(s). There should be continuity between
the cavity for relay terminal 87 and the horn relay
output circuit cavity of each horn wire harness con-
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. The horn relay coil ground terminal can
also be grounded by the Body Control Module (BCM)
in response to certain inputs related to the RKE sys-
tem or the Vehicle Theft Security 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 - DIAGNOSIS AND TEST-
ING).
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.
Fig. 2 Horn Relay
30 - COMMON FEED
85 - COIL GROUND
86 - COIL BATTERY
87 - NORMALLY OPEN
87A - NORMALLY CLOSED
WJHORN 8H - 5
HORN RELAY (Continued)

HORN SWITCH
DESCRIPTION
A center-blow, normally open, resistive membrane-
type horn switch is secured in a plastic tray that is
inserted in a pocket sewn on the front of the driver
side airbag retainer strap. The horn switch is con-
cealed behind the driver side airbag module trim
cover in the center of the steering wheel. 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 and plastic tray
are serviced as a unit. If the horn switch is damaged
or faulty, or if the driver side airbag is deployed, the
horn switch and tray must be replaced as a unit.
OPERATION
When the center area of the driver side airbag trim
cover is depressed, the electrically conductive grids
on the facing surfaces of the horn switch membranes
contact each other, closing the switch circuit. The
completed horn switch circuit provides a ground for
the control coil side of the horn relay, which activates
the relay. When the horn switch is released, the
resistive tension of the convex membrane separates
the two electrically conductive grids and opens the
switch circuit.
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: ON VEHICLES EQUIPPED WITH AIR-
BAGS, REFER TO ELECTRICAL, RESTRAINTS
BEFORE ATTEMPTING ANY STEERING WHEEL,
STEERING COLUMN, OR INSTRUMENT PANEL
COMPONENT DIAGNOSIS OR SERVICE. FAILURE
TO TAKE THE PROPER PRECAUTIONS COULD
RESULT IN ACCIDENTAL AIRBAG DEPLOYMENT
AND POSSIBLE PERSONAL INJURY.
(1) Disconnect and isolate the battery negative
cable. Remove the steering column opening cover
from the instrument panel.
(2) Check for continuity between the metal steer-
ing column jacket and a good ground. There should
be continuity. If OK, go to Step 3. If not OK, refer to
Steering, Column for proper installation of the steer-
ing column.
(3) Remove the driver side airbag module from the
steering wheel. Disconnect the horn switch wire har-
ness connectors from the driver side airbag module.
(4) Remove the horn relay from the Power Distri-
bution Center (PDC). Check for continuity between
the steering column half of the horn switch feed wire
harness connector and a good ground. There should
be no continuity. If OK, go to Step 5. If not OK,
repair the shorted horn relay control circuit to the
horn relay in the PDC as required.
(5) 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 PDC. There should be continu-
ity. If OK, go to Step 6. If not OK, repair the open
horn relay control circuit to the horn relay in the
PDC as required.
Fig. 3 Power Distribution Center
1 - RIGHT FENDER
2 - BATTERY
3 - POWER DISTRIBUTION CENTER
4 - COVER
8H - 6 HORNWJ
HORN RELAY (Continued)