Page 497 of 2585

OPERATION
When the rear window defogger button is
depressed to the On position, current is directed to
the rear defogger grid lines and the heated power
mirrors (if equipped). The heated grid lines heat the
glass to help clear the rear window and side mirror
surfaces of fog or frost.
The defogger system is controlled by a momentary
switch located in the A/C-heater control on the
instrument panel. A yellow indicator in the switch
will illuminate to indicate when the defogger system
is turned on. The integrated power module (IPM)
contains the defogger system control circuitry.
NOTE:
The rear window defogger turns off automat-
ically after approximately 10 minutes of initial opera-
tion. Each following activation cycle of the defogger
system will last approximately five minutes.
The defogger system will be automatically 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 auto-
matically 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 defog-
ger switch a second time.
DIAGNOSIS AND TESTING - REAR WINDOW
DEFOGGER SYSTEM
The electrically heated rear window defogger oper-
ation can be checked on the vehicle in the following
manner:
(1) Turn the ignition switch to the On position.
(2) Make sure that the defogger switch is Off.
(3) Using a ammeter on the battery, turn the rear
defogger control switch to the On position, a distinct
increase in amperage draw should be noted.
(4) The rear window defogger operation can be
checked by feeling the glass. A distinct difference in
temperature between the grid lines and adjacent
clear glass should be detected in three to four min-
utes of operation.
(5) Using a DC voltmeter, contact the negative
lead to Point B, and the positive lead to Point A (Fig.
2). The voltmeter should read 10-14 volts.
NOTE: Illumination of the LED indicator means that
there is power available at the switch, but does not
necessarily verify system operation.
(6) If turning the defogger switch On produced no
distinct current draw on the ammeter, the problem
should be isolated in the following manner:²Confirm that the ignition switch is On.
²Make sure that the heated rear window feed
wire is connected to the terminal and that the
ground wire is in fact grounded.
²Make sure that fuse 13 (40 amp) in the inte-
grated power module (IPM) is OK.
(7) When the above steps have been completed and
the system is still inoperative, one or more of the fol-
lowing could be defective. It may be necessary to con-
nect a DRBIIItscan tool to perform further
diagnostics. Refer to Body Diagnostic Procedures.
²Rear window defogger switch in the A/C-heater
control.
²J1850 bus communication between the A/C-
heater control and the front control module (FCM).
²Rear window defogger relay in the IPM.
²Rear window defogger relay control circuity in
the IPM.
²Check for a loose wire connector or a wire
pushed out of a connector.
²Rear window grid lines (all grid lines would
have to be broken, or one of the feed wires not con-
nected for the system to be inoperative).
(8) If turning the rear window defogger switch On
produces severe voltmeter deflection, the circuit
should be closely checked for a shorting condition.
(9) If the system operation has been verified but
LED indicator does not illuminate, replace the A/C-
heater control.
(10) For detailed wiring information, refer to Wir-
ing Diagrams.
Fig. 2 Grid Line Test
1 - VOLTMETER
2 - VOLTAGE FEED (A)
3 - FEED WIRE
4 - MID-POINT (C)
5 - HEATED WINDOW GRID
6 - GROUND WIRE
7 - GROUND (B)
8G - 2 HEATED GLASSRS
HEATED GLASS (Continued)
Page 498 of 2585

REAR WINDOW DEFOGGER
RELAY
DESCRIPTION
The rear window defogger relay (Fig. 3) is a Inter-
national Standards Organization (ISO)-type relay.
Relays conforming to the ISO specifications have
common physical dimensions, current capacities, ter-
minal patterns, and terminal functions. The rear
window defogger relay is a electromechanical device
that switches battery current through a fuse in the
integrated power module (IPM) to the rear window
defogger grid and switches battery current through a
positive thermal coefficient (PTC) in the IMP to the
outside mirror heating grids. The relay is energized
when the relay coil is provided a ground path by the
rear window defogger relay control in the front con-
trol module (FCM).
The rear window defogger relay is located in the
IPM in the engine compartment. See the fuse and
relay layout map on the inner surface of the IPM
cover for rear window defogger relay identification
and location.
The rear window defogger relay cannot be adjusted
or repaired and, if damaged or faulty, 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 movablecontact 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.
Refer to the appropriate wiring information for
diagnosis and testing of the ISO relay and for com-
plete rear window defogger system wiring diagrams.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the cover from the Integrated Power
Module (IPM) (Fig. 4).
(3) Refer to the fuse and relay layout map molded
into the inner surface of the IPM cover for rear win-
dow defogger relay identification and location.
(4) Remove the rear window defogger relay from
the IPM.
INSTALLATION
(1) Refer to the fuse and relay layout map molded
into the inner surface of the Integrated Power Mod-
ule (IPM) cover for rear window defogger relay iden-
tification and location.
Fig. 3 Rear Window Defogger Relay
30 - COMMON FEED
85 - COIL GROUND
86 - COIL BATTERY
87 - NORMALLY OPEN
87A - NORMALLY CLOSED
Fig. 4 Integrated Power Module
1 - BATTERY THERMAL GUARD
2 - INTEGRATED POWER MODULE (IPM)
3 - FRONT CONTROL MODULE
RSHEATED GLASS8G-3
Page 499 of 2585

(2) Position the rear window defogger relay into
the proper receptacle in the IPM.
(3) Align the rear window defogger relay terminals
with the terminal cavities in the IPM receptacle.
(4) Push down firmly on the rear window defogger
relay until the terminals are fully seated in the ter-
minal cavities in the IPM receptacle.
(5) Install the cover onto the IPM.
(6) Reconnect the battery negative cable.
REAR WINDOW DEFOGGER
SWITCH
DESCRIPTION
The rear window defogger switch is integrated into
the A/C-heater control mounted in the center of the
instrument panel (Fig. 5). The rear window defogger
switch and the rear window defogger LED indicator
cannot be repaired and, if faulty or damaged, the
A/C-heater control must be replaced.
OPERATION
An LED indicator will illuminate when the rear
window defogger switch is activated. The switch
energizes the A/C-heater control module which then
requests the front control module (FCM) to activate
the rear window defogger relay via the J1850 com-
munication bus. The rear window defogger relay con-
trols the current to flow to the grids of the rear
window defogger and the heated power side view
mirrors. The defogger relay will be on for approxi-
mately 10 minutes or until the control switch or igni-
tion is turned off.
REAR WINDOW DEFOGGER
GRID
STANDARD PROCEDURE - GRID LINE AND
TERMINAL REPAIR
REAR WINDOW DEFOGGER GRID LINE REPAIR
WARNING: THE REPAIR KIT CONTAINS EPOXY
RESIN AND AMINE TYPE HARDENER WHICH MAY
CAUSE SKIN OR EYE IRRITATION AND CAN BE
HARMFUL IF SWALLOWED. USE WITH ADEQUATE
VENTILATION. DO NOT USE NEAR FIRE OR OPEN
FLAME THE CONTENTS CONTAIN FLAMMABLE
SOLVENTS. KEEP OUT OF REACH OF CHILDREN.
²DO NOT TAKE INTERNALLY, IF SWALLOWED
INDUCE VOMITING AND CALL A PHYSICIAN IMME-
DIATELY.
²IF SKIN CONTACT OCCURS, WASH AFFECTED
AREAS WITH SOAP AND WATER.
²IF EYE CONTACT OCCURS, FLUSH WITH
PLENTY OF WATER.
The repair of the grid lines is possible using the
MopartGrid Line Repair Package or an equivalent.
(1) Mask the repair area so the conductive epoxy
can be extended onto the grid line(s) or the bus bar
(Fig. 6).
(2) Follow the instructions in the repair kit for
preparing the damaged area.
(3) Remove the package separator clamp and mix
the conductive epoxy thoroughly. Fold in half and cut
the center corner to dispense the epoxy.
(4) Apply the conductive epoxy through the slit in
the masking tape. Overlap both ends of the break(s)
by 19 mm (3/4 inch).
(5) Carefully remove the masking tape from the
grid line(s).
CAUTION: To prevent the glass from fracturing, do
not allow the glass surface to exceed 204É C (400É
F).
(6) Allow the epoxy to cure 24 hours at room tem-
perature or use a heat gun with a 260É to 371É C
(500É to 700É F) range for 15 minutes. Hold the heat
gun approximately 254 mm (10 inches) from the
repaired area.
(7) After the conductive epoxy is properly cured,
verify operation of the rear window defogger.
Fig. 5 A/C-Heater Control - Typical
1 - TRIM BEZEL
2 - INFRARED TEMPERATURE SENSOR
3 - A/C REQUEST SWITCH
4 - REAR WINDOW DEFOGGER/HEATED MIRRORS SWITCH
5 - FRONT WINDOW DEFROSTER MODE SELECTOR
8G - 4 HEATED GLASSRS
REAR WINDOW DEFOGGER RELAY (Continued)
Page 500 of 2585

REAR WINDOW DEFOGGER GRID TERMINAL REPAIR
WARNING: THE REPAIR KIT CONTAINS EPOXY
RESIN AND AMINE TYPE HARDENER WHICH MAY
CAUSE SKIN OR EYE IRRITATION AND CAN BE
HARMFUL IF SWALLOWED. USE WITH ADEQUATE
VENTILATION. DO NOT USE NEAR FIRE OR OPEN
FLAME THE CONTENTS CONTAIN FLAMMABLE
SOLVENTS. KEEP OUT OF REACH OF CHILDREN.
²DO NOT TAKE INTERNALLY, IF SWALLOWED
INDUCE VOMITING AND CALL A PHYSICIAN IMME-
DIATELY.
²IF SKIN CONTACT OCCURS, WASH AFFECTED
AREAS WITH SOAP AND WATER.
²IF EYE CONTACT OCCURS, FLUSH WITH
PLENTY OF WATER.
If the rear window defogger grid terminal(s) is
damaged or separated from the rear window, the
repair of the grid terminals is possible using the
MopartGrid Line Repair Package or an equivalent.(1) If the grid terminal(s) is broken and a portion
of the terminal is still attached to the heating grid,
remove the portion of the clip remaining in the wire
harness connector(s).
(2) Mask the areas so the conductive epoxy can be
extended onto the adjacent grid line(s) as well as the
bus bar.
(3) Apply a thin layer of conductive epoxy to the
area where the terminal(s) where fastened and to the
adjacent grid line(s).
NOTE: To prevent the terminal(s) from moving while
the epoxy is curing, a wedge or clamp must be
used.
(4) Apply a thin layer of conductive epoxy on the
terminal(s) and properly orient the terminal(s) at the
desired location(s).
CAUTION: To prevent the glass from fracturing, do
not allow the glass surface to exceed 204É C (400É
F).
(5) Allow the epoxy to cure 24 hours at room tem-
perature or use a heat gun with a 260É to 371É C
(500É to 700É F) range for 15 minutes. Hold the heat
gun approximately 254 mm (10 inches) from repaired
area.
NOTE: To ensure proper installation, do not attach
the wire harness connector(s) to the terminal(s)
until the epoxy is completely cured.
(6) After the conductive epoxy has properly cured,
remove the wedge or clamp from the terminal(s),
reconnect the wire harness connector(s) and verify
operation of the rear window defogger.
Fig. 6 Grid Line Repair
1 - BREAK
2 - GRID LINE
3 - MASKING TAPE
RSHEATED GLASS8G-5
REAR WINDOW DEFOGGER GRID (Continued)
Page 501 of 2585

HEATED MIRRORS
TABLE OF CONTENTS
page page
HEATED MIRRORS
DESCRIPTION..........................6OPERATION............................6
HEATED MIRRORS
DESCRIPTION
The optional heated mirror system only operates in
concert with the rear window defogger system, and
will be automatically shut 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
heated mirror system will automatically shut off
after about five minutes.
The heated mirror system will automatically shut
off if the ignition switch is turned to the Off position,
or it can be shut off manually by pressing the rear
window defogger switch a second time.
OPERATION
When the rear window defogger switch (Fig. 1) is
in the On position, an electric heater grid located
behind the glass of each of the outside rear view mir-
rors is energized. When energized, each of these
heater grids produce heat to help clear the outside
rear view mirrors of ice, snow, or fog.
The heated mirror system is controlled by a
momentary rear window defogger switch on the A/C-
heater control. An amber indicator lamp in the
switch will illuminate to indicate when the defogger
system is turned on.
If the outside mirror heating grids are both inoper-
ative, refer to DIAGNOSIS AND TESTING - REARWINDOW DEFOGGER SYSTEM in his group. If
only one of the outside mirror heating grids is inop-
erative, Refer to 8 - ELECTRICAL/POWER 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 assembly must be replaced.
Fig. 1 A/C-Heater Control Panel
1 - TRIM BEZEL
2 - INFRARED TEMPERATURE SENSOR
3 - A/C REQUEST SWITCH
4 - REAR WINDOW DEFOGGER/HEATED MIRRORS SWITCH
5 - FRONT WINDOW DEFROSTER MODE SELECTOR
8G - 6 HEATED MIRRORSRS
Page 502 of 2585

HEATED SEAT SYSTEM
TABLE OF CONTENTS
page page
HEATED SEAT SYSTEM
DESCRIPTION..........................7
OPERATION............................8
DIAGNOSIS AND TESTING - HEATED SEAT
SYSTEM.............................8
DRIVER HEATED SEAT SWITCH
DESCRIPTION..........................8
OPERATION............................8
DIAGNOSIS AND TESTING - DRIVER HEATED
SEAT SWITCH.........................9
REMOVAL.............................10
INSTALLATION.........................10
HEATED SEAT ELEMENTS
DESCRIPTION.........................10
OPERATION...........................10
DIAGNOSIS AND TESTING - HEATED SEAT
ELEMENTS..........................10REMOVAL.............................11
INSTALLATION.........................11
HEATED SEAT SENSOR
DESCRIPTION.........................12
OPERATION...........................12
DIAGNOSIS AND TESTING - HEATED SEAT
SENSOR............................12
PASSENGER HEATED SEAT SWITCH
DESCRIPTION.........................12
OPERATION...........................12
DIAGNOSIS AND TESTING - PASSENGER
HEATED SEAT SWITCH.................13
REMOVAL.............................14
INSTALLATION.........................14
HEATED SEAT SYSTEM
DESCRIPTION
Vehicles with the heated seat option can be visu-
ally identified by the two separate heated seatswitches located in the instrument panel center
stack, just above the radio (Fig. 1). The heated seat
system allows the front seat driver and passenger to
select from two different levels of supplemental elec-
trical seat heating (HI/LO), or no seat heating to suit
their individual comfort requirements. The heated
seat system for this vehicle includes the following
major components, which are described in further
detail later in this section:
²Heated Seat Elements- Four heated seat ele-
ments are used per vehicle, two for each front seat.
One heated seat element is integral to each front
seat trim cover, one in the seat back and one in the
seat bottom (cushion). Service replacement heating
elements are available, refer to heated seat elements
later in this section for additional information.
²Heated Seat Modules- Two heated seat mod-
ules are used per vehicle. One module is mounted to
each of the seat cushion pans, located under the for-
ward edge of each front seat. Refer to heated seat
module in the electronic control modules section of
the service manual for additional information.
²Heated Seat Sensors- Two heated seat sen-
sors are used per vehicle, one for each front seat. The
heated seat sensors are integral to each of the heated
seat bottoms (cushions).
²Heated Seat Switch- Two heated seat
switches are used per vehicle, one for the driver and
one for the passenger side front seats. The switches
are mounted in the instrument panel center stack.
Fig. 1 HEATED SEAT SWITCH LOCATIONS
1 - HEATED SEAT SWITCHES
RSHEATED SEAT SYSTEM8G-7
Page 503 of 2585

Refer to the description of the heated seat switch
later in this section for additional information.
Hard wired circuitry connects the heated seat sys-
tem components to each other through the electrical
system of the vehicle. These hard wired circuits are
integral to several wire harnesses, which are routed
throughout the vehicle and retained by many differ-
ent methods. These circuits may be connected to each
other, to the vehicle electrical system and to the
heated seat system components through the use of a
combination of soldered splices and splice block con-
nectors. Refer to Wiring for complete system wiring
schematics. The wiring information also includes the
proper wire and connector repair procedures, further
details on wire harness routing and retention, as well
as pin-out and location views for the various wire
harness connectors, splices and grounds.
OPERATION
The heated seat system components operate on
battery current received through a fuse in the Inte-
grated Power Module (IPM) on a fused ignition
switch output (run) circuit from the Body Control
Module. The system will only operate when the igni-
tion switch is in the On position. The heated seat
system will be turned Off automatically whenever
the ignition switch is turned to any position except
On. Also, the heated seat system will not operate
when the surface temperature of the seat cushion
cover at either heated seat sensor is above the
designed temperature set points of the system. See
the owner's manual in the vehicle glove box for more
information on the features, use and operation of the
heated seat system.
DIAGNOSIS AND TESTING - HEATED SEAT
SYSTEM
The most reliable, efficient, and accurate means to
diagnose the heated seat system requires the use of a
DRBIIItscan tool and the proper Diagnostic Proce-
dures manual. The DRBIIItscan tool can provide
confirmation that the PCI data bus is functional, that
all of the electronic modules are sending and receiv-
ing the proper messages on the PCI data bus, and
that the heated seat modules are receiving the
proper hard wired inputs from and relaying the
proper hard wired outputs to the Body Control Mod-
ule in order to perform its functions. Refer toWiring
Diagramsfor complete wiring schematics. The wir-
ing information also includes the proper wire and
connector repair procedures, further details on wire
harness routing and retention, as well as pin-out and
location views for the various wire harness connec-
tors, splices and grounds.
DRIVER HEATED SEAT
SWITCH
DESCRIPTION
The heated seat switches are mounted in the
instrument panel center bezel (Fig. 2). The two three-
position rocker-type switches, one switch for each
front seat, are incorporated into one large switch
assembly that also includes the hazard, rear window
wiper and washer switches. The heated seat switches
each provide a resistor multiplexed signal to its
respective Heated Seat Module (HSM) through sepa-
rate hard wired circuits. Each switch has an Off,
Low, and High position so that both the driver and
the front seat passenger can select a preferred seat
heating mode. Each switch has two Light-Emitting
Diodes (LED) which light to indicate that the heater
for the seat is turned on.
The heated seat switches and their LEDs cannot
be repaired. If either switch or LED is faulty or dam-
aged, the entire switch assembly must be replaced.
OPERATION
There are three positions that can be selected with
each of the heated seat switches: Off, Low, or High.
When the left side of the switch rocker is fully
depressed, the Low position is selected and the low
position LED indicator illuminates. When the right
side of the switch rocker is fully depressed, the High
position is selected and the high position LED indi-
Fig. 2 HEATED SEAT SWITCH LOCATION
1 - HEATED SEAT SWITCHES
8G - 8 HEATED SEAT SYSTEMRS
HEATED SEAT SYSTEM (Continued)
Page 504 of 2585

cator illuminates. When the switch rocker is moved
to its neutral position (middle), Off is selected and
both LED indicators are extinguished.
Each switch provides separate resistor multiplexed
hard wire inputs to its respective Heated Seat Mod-
ule (HSM) to indicate the selected switch position.
The heated seat module responds to the heated seat
switch status messages by controlling 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 - DRIVER HEATED
SEAT SWITCH
For complete circuit diagrams, refer toWiring
Diagrams.
WARNING: REFER TO THE RESTRAINTS SECTION
OF THIS MANUAL BEFORE ATTEMPTING ANY
STEERING WHEEL, STEERING COLUMN, SEAT OR
INSTRUMENT PANEL COMPONENT DIAGNOSIS OR
SERVICE. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
CHECKING SWITCH SIGNAL AND WIRING AT THE
MODULE
(1) Disconnect and isolate the battery negative
cable.
(2) Access and disconnect the gray 4-way connector
from the heated seat module. Visually inspect wiring
terminals for damage that would prevent positive
connection. If not OK, repair or replace the necessary
components.
(3) Place the heated seat switch in the LO posi-
tion. Using an Ohmmeter, check the resistance
between cavities 2 and 3 of the gray connector noted
above. Resistance should be about 3.5 kilohms (3500
ohms). If not OK, check resistance directly at switch,
as noted below. If OK, proceed to the next step. If not
OK, replace the faulty switch.
(4) Place the heated seat switch in the HI position.
Using an ohmmeter, check the resistance between
cavities 2 and 3 of the gray connector noted above.
Resistance should be about 1.4 kilohms (1400 ohms).
If not OK, check resistance directly at switch, as
noted below. If OK, proceed. If not OK replace the
faulty switch.
(5) With the system ON in the HI position, check
for battery voltage and ground at cavities 4 and 1. If
OK, proceed with testing remaining components. If
not OK, repair open or shorted wiring.
CHECKING SWITCH ONLY
(1) Disconnect and isolate the battery negative
cable. Remove the center bezel from the instrument
panel (Refer to 23 - BODY/INSTRUMENT PANEL/
INSTRUMENT PANEL CENTER BEZEL -
REMOVAL). Check for continuity between the
ground circuit cavity (#10) of the instrument panel
switch bank electrical connector and a good ground.
There should be continuity. If OK, go to Step 2. If not
OK, repair the open ground circuit to ground as
required.
(2) Reconnect the battery negative cable. Turn the
ignition switch to the On position. Check for battery
voltage at the fused ignition switch output (run) cir-
cuit cavity of the instrument panel switch bank con-
nector (#4). If OK, turn the ignition switch to the Off
position, and go to Step 3. If not OK, repair the open
fused ignition switch output (run) circuit as required.
(3) Test the heated seat switch as shown in the
Heated Seat Switch Test chart and the connector pin-
out below (Fig. 3). If OK, go to Step 4. If not OK,
replace the faulty switch bank assembly.
DRIVER HEATED SEAT SWITCH TEST
SWITCH
POSITIONRESISTANCE
BETWEENRESISTANCE
(OHMS)
Off Pin4&5OPEN
Low Pin4&53570
High Pin4&51430
All resistance values are 1%.
Fig. 3 Instrument Panel Switch Bank Connector
RSHEATED SEAT SYSTEM8G-9
DRIVER HEATED SEAT SWITCH (Continued)