2003 JEEP GRAND CHEROKEE Cable

(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)

(3) See the fuse and relay layout label affixed to
the underside of the PDC cover for starter relay iden-
tification and location.
(4) Remove the starter relay from the PDC.
INSTALLATION
(1) See the fuse and relay layout label affixed to
the underside of the PDC cover for the proper starter
relay location.
(2) Position the starter relay in the proper recep-
tacle in the PDC.(3) Align the starter relay terminals with the ter-
minal cavities in the PDC receptacle.
(4) Push down firmly on the starter 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.
8F - 40 STARTINGWJ
STARTER MOTOR RELAY (Continued)

²Passenger Door Module (PDM)- Refer to
Electronic Control Modules for more information.
OPERATION - REAR WINDOW DEFOGGER
The rear window defogger system is controlled by a
momentary switch that is integral to the a/c heater
control located in the center stack area of the instru-
ment panel. A Light-Emitting Diode (LED) in the
switch button will light to indicate when the rear
window defogger system is turned on. The BCM,
which contains the rear window defogger system
timer and control logic, monitors the status of the
defogger switch through a hard-wired input. The
BCM then sends control outputs through a hard
wired circuit to energize or de-energize the defogger
relay.
The electrically heated outside rear view mirror
heating grids are also controlled by the rear window
defogger switch. When the BCM receives an input
from the switch, it sends a defogger switch status
message to the DDM and the PDM over the PCI data
bus. The DDM and PDM respond to the defogger
switch status messages by energizing or de-energiz-
ing the battery current feed to their respective out-
side rear view mirror heating grids.
The rear window defogger system will be automat-
ically turned off after a programmed time interval of
about ten minutes. After the initial time interval has
expired, if the defogger switch is turned on again
during the same ignition cycle, the defogger system
will automatically turn off after about five minutes.
The defogger system will automatically shut off if the
ignition switch is turned to the Off position, or it can
be turned off manually by depressing the rear win-
dow defogger switch again.
See the owner's manual in the vehicle glove box for
more information on the features, use and operation
of the rear window defogger system.
DIAGNOSIS AND TESTING - REAR WINDOW
DEFOGGER SYSTEM
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.For complete circuit diagrams, (Refer to Appropri-
ate Wiring Information). The operation of the electri-
cally heated rear window defogger system can be
confirmed in one of the following manners:
1. Turn the ignition switch to the On position.
While monitoring the instrument panel voltmeter,
depress the rear window defogger switch to the On
position. When the rear window defogger switch is
turned On, a distinct voltmeter needle deflection
should be noted.
2. Turn the ignition switch to the On position.
Depress the rear window defogger switch to the On
position. The rear window defogger operation can be
checked by feeling the rear window or outside rear
view mirror glass. A distinct difference in tempera-
ture between the grid lines and the adjacent clear
glass or the mirror glass can be detected within three
to four minutes of operation.
3. Using a 12-volt DC voltmeter, contact the rear
glass heating grid terminal A (right side) with the
negative lead, and terminal B (left side) with the pos-
itive lead (Fig. 1). The voltmeter should read battery
voltage.
The above checks will confirm rear window defog-
ger system operation. Illumination of the rear win-
dow defogger switch LED indicator means that there
is battery current available at the output of the rear
window defogger relay, but does not confirm that bat-
tery current is reaching the rear glass heating grid
lines.
If the rear window defogger system does not oper-
ate, the problem should be isolated in the following
manner:
Fig. 1 REAR WINDOW GLASS GRID TEST
1 - TERMINAL ªAº
2 - TERMINAL ªBº
3 - FEED WIRE
4 - MID-POINT ªCº (TYPICAL)
5 - HEATED REAR WINDOW DEFOGGER GRID
6 - GROUND WIRE
8G - 2 HEATED GLASSWJ
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)

repaired and, if faulty or damaged, the entire a/c
heater control must be replaced. (Refer to 24 - HEAT-
ING & AIR CONDITIONING/CONTROLS/A/C
HEATER CONTROL - REMOVAL)
OPERATION
When the rear window defogger switch push but-
ton is depressed, it momentarily closes the rear win-
dow defogger switch sense circuit for the BCM to
ground. The BCM monitors the rear window defogger
switch sense circuit. Each time the BCM rear win-
dow defogger timer and logic circuitry sees another
input from the switch, it toggles a control output to
the rear window defogger relay. Energizing the rear
window defogger relay provides electrical current to
the rear window defogger grid and to the LED indi-
cator in the switch, which lights to indicate when the
defogger system is turned on. A dedicated fuse in the
junction block protects the rear window defogger
relay output circuit to the LED indicator.
DIAGNOSIS AND TESTING - REAR WINDOW
DEFOGGER SWITCH
For complete circuit diagrams, refer to the Appro-
priate 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 a/c heater control from the instru-
ment panel and disconnect the 11-way (manual tem-
perature control) or 16-way (automatic zone control)
instrument panel wire harness connector from the a/c
heater control receptacle.
(2) Check for continuity between the ground cir-
cuit cavity of the 11-way or 16-way instrument panel
wire harness connector for the a/c heater control and
a good ground. There should be continuity. If OK, go
to Step 3. If not OK, repair the open ground circuit to
ground as required.
(3) Connect two jumper wires to the a/c heater
control 11-way or 16-way connector receptacle. Con-
nect one jumper from the ground circuit terminal inthe 11-way or 16-way a/c heater control connector
receptacle to a good ground. Connect the other
jumper from the fused rear window defogger relay
output circuit terminal of the 11-way or 16-way con-
nector receptacle to a 12-volt battery feed. The rear
window defogger switch LED indicator should light.
If OK, go to Step 4. If not OK, replace the faulty a/c
heater control.
(4) Check for continuity between the ground cir-
cuit and rear window defogger switch sense circuit
terminals of the 11-way or 16-way a/c heater control
connector receptacle. There should be momentary
continuity as the rear window defogger switch push
button is depressed, and then no continuity. If OK, go
to Step 5. If not OK, replace the faulty a/c heater
control.
(5) Disconnect the 22-way instrument panel wire
harness connector from the Body Control Module
(BCM) connector receptacle. Check for continuity
between the rear window defogger switch sense cir-
cuit cavity of the 11-way or 16-way instrument panel
wire harness connector for the a/c heater control and
a good ground. There should be no continuity. If OK,
go to Step 6. If not OK, repair the shorted rear win-
dow defogger switch sense circuit as required.
(6) Check for continuity between the rear window
defogger switch sense circuit cavities of the 11-way or
16-way instrument panel wire harness connector for
the a/c heater control and the 22-way instrument
panel wire harness connector for the BCM. There
should be continuity. If OK, refer to (Refer to 8 -
ELECTRICAL/HEATED GLASS/REAR WINDOW
DEFOGGER RELAY - DIAGNOSIS AND TESTING).
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.
(Refer to 24 - HEATING & AIR CONDITIONING/
CONTROLS/A/C HEATER CONTROL - REMOVAL)
WJHEATED GLASS 8G - 7
REAR WINDOW DEFOGGER SWITCH (Continued)

HEATED MIRRORS
TABLE OF CONTENTS
page page
HEATED MIRRORS
DESCRIPTION..........................8
OPERATION............................8DIAGNOSIS AND TESTING - HEATED
MIRRORS............................8
HEATED MIRRORS
DESCRIPTION
Electrically heated outside rear view mirrors are
optional equipment on this model. These mirrors fea-
ture an electric heating grid located behind the mir-
ror glass of each power operated outside rear view
mirror. These heating grids consist of a single resis-
tor wire routed in a grid-like pattern and captured
between two thin sheets of plastic. When electrical
current is passed through the resistor wire, it pro-
duces enough heat energy to clear the outside mirror
glass of ice, snow or fog. Battery current is directed
to the outside mirror heating grid only when the rear
window defogger switch is in the On position.
If the outside mirror heating grids and the rear
window heating grid are all inoperative, (Refer to 8 -
ELECTRICAL/HEATED GLASS - DIAGNOSIS AND
TESTING - REAR WINDOW DEFOGGER SYSTEM).
If the outside mirror heating grids are inoperative,
but the rear window heating grid is operating as
designed, (Refer to 8 - ELECTRICAL/HEATED MIR-
RORS - DIAGNOSIS AND TESTING)
The heating grid behind each outside mirror glass
cannot be repaired and, if faulty or damaged, the
entire power mirror unit must be replaced. Refer to
Power Mirrors for the procedures.
OPERATION
The outside mirror heating grids are energized and
de-energized by the Driver Door Module (DDM) and
the Passenger Door Module (PDM) based upon the
rear window defogger switch status. The Body Con-
trol Module (BCM) monitors the rear window defog-ger switch. When the BCM receives an input from
the switch, it sends a defogger switch status message
to the DDM and the PDM over the Programmable
Communications Interface data bus. The DDM and
PDM respond to the defogger switch status messages
by energizing or de-energizing the battery current
feed to their respective outside rear view mirror
heating grids.
DIAGNOSIS AND TESTING - HEATED MIRRORS
For circuit descriptions and diagrams, (Refer to
Appropriate Wiring Information).
(1) If both mirror heaters are inoperative, check
for proper operation of the Rear Window Defogger
System. (Refer to 8 - ELECTRICAL/HEATED GLASS
- DIAGNOSIS AND TESTING - REAR WINDOW
DEFOGGER SYSTEM). If Rear Window Defogger
System operates correctly, or if only one mirror
heater is inoperative, go to Step 2.
(2) Disconnect and isolate the battery negative
cable. Remove the front door trim panel on the side
of the inoperative mirror heater. Go to Step 3.
(3) Disconnect the door wire harness connector
from the door module connector receptacle. Check for
continuity between the mirror heater 12 volt supply,
and the mirror heater ground. There should be con-
tinuity. If OK, go to Step 4. If not OK, check for con-
tinuity of the individual circuits between the power
mirror and the door module, and of the mirror heater
grid right at the power mirror.
(4) Use a DRB IIItand (Refer to Appropriate
Diagnostic Information) to test the door module and
the PCI data bus.
8G - 8 HEATED MIRRORSWJ