2002 JEEP LIBERTY Battery circuit

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 electro-
magnetic coil is energized, it draws the movable con-
tact away from normally closed fixed contact, and
holds it against the other (normally open) fixed con-
tact.
When electromagnetic coil is de-energized, spring
pressure returns movable contact to normally closed
position. The resistor or diode is connected in parallel
with electromagnetic coil within relay, and helps to
dissipate voltage spikes produced when coil is de-en-
ergized.
DIAGNOSIS AND TESTING - STARTER RELAY
The starter relay is located in the Power Distribu-
tion Center (PDC) in engine compartment. Refer to
label on PDC cover for relay location.
RELAY TEST
(1) Remove starter relay (Fig. 13) from PDC.
(2) A relay in 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 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 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 following Relay Circuit Test.
If not OK, replace 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 open cir-
cuit to fused B(+) fuse in PDC as required.
(2) The relay normally closed terminal (87A) is
connected to terminal 30 in 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 common feed terminal (30) in energized
position. This terminal supplies battery voltage to
starter solenoid field coil. There should be continuity
between cavity for relay terminal 87 and starter sole-
noid terminal at all times. If OK, go to Step 4. If not
OK, repair open engine starter motor relay output
circuit to starter solenoid as required.
(4) The coil battery terminal (86) is connected to
electromagnet in relay. It is energized when ignition
switch is held in Start position. On vehicles with amanual transmission, the clutch pedal must be
blocked in fully depressed position for this test.
Check for battery voltage at cavity for relay terminal
86 with ignition switch in Start position, and no volt-
age when ignition switch is released to On position.
If OK, go to Step 5. If not OK with a manual trans-
mission, disconnect clutch pedal position switch wire
harness connector and install a jumper wire between
two cavities in body half of connector and check for
battery voltage again at cavity for relay terminal 86.
If now OK, replace faulty clutch pedal position
switch. If still not OK with a manual transmission or
if not OK with an automatic transmission, check for
open or shorted fused ignition switch output (start)
circuit to ignition switch and repair as required. If
fused ignition switch output (start) circuit is OK,
refer toIgnition Switch and Key Lock Cylinder.
(5) The coil ground terminal (85) is connected to
electromagnet in relay. On vehicles with manual
transmission, it is grounded at all times. On vehicles
with automatic transmission, it is grounded through
park/neutral position switch only when gearshift
selector lever is in Park or Neutral positions. Check
for continuity to ground at cavity for relay terminal
85. If not OK with a manual transmission, repair
open park/neutral position switch sense circuit to
ground as required. If not OK with an automatic
transmission, check for open or shorted park/neutral
position switch sense circuit to park/neutral position
switch and repair, as required. If park/neutral posi-
tion switch sense circuit checks OK, refer toPark/
Neutral Position Switch.
Fig. 13 STARTER RELAY (ISO MICRO RELAY)
30 - COMMON FEED
85 - COIL GROUND
86 - COIL BATTERY
87 - NORMALLY OPEN
87A - NORMALLY CLOSED
8F - 42 STARTING SYSTEMKJ
STARTER MOTOR RELAY (Continued)

HEATED SYSTEMS
TABLE OF CONTENTS
page page
HEATED MIRRORS......................... 1
WINDOW DEFOGGER....................... 3HEATED SEAT SYSTEM.................... 10
HEATED MIRRORS
TABLE OF CONTENTS
page page
HEATED MIRRORS
DESCRIPTION..........................1
OPERATION............................1DIAGNOSIS AND TESTING - HEATED
MIRRORS............................1
HEATED MIRRORS
DESCRIPTION
Vehicles equipped with the optional heated mirror
package have an electric heating grid located behind
the mirror glass of each outside rear view mirror.
The heated mirrors are controlled by the rear win-
dow defogger switch. Electrical current is directed to
the heating grid inside the mirror 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). If the outside mirror heating grids are
inoperative, but the rear window heating grid is
operating as designed, (Refer to 8 - ELECTRICAL/
HEATED MIRRORS - 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 8
- ELECTRICAL/POWER MIRRORS/SIDEVIEW MIR-
ROR - REMOVAL) and (Refer to 8 - ELECTRICAL/
POWER MIRRORS/SIDEVIEW MIRROR -
INSTALLATION).
OPERATION
The heated mirror is controlled by the rear window
defogger switch. The only time that the heated mir-
ror is on is when the rear window defogger is on. The
mirror should become warm to the touch.
DIAGNOSIS AND TESTING - HEATED MIRRORS
For circuit descriptions and diagrams (Refer to
Appropriate Wiring Information).
(1) Check the fuse in the junction block. If OK, go
to Step 2. If not OK, repair the shorted circuit or
component as required and replace the faulty fuse.
(2) Turn the ignition switch to the On position.
Check for battery voltage at the fuse in the junction
block. If OK, go to Step 3. If not OK, repair the open
circuit to the ignition switch as required.
(3) Disconnect and isolate the battery negative
cable. Remove the front door trim panel on the side
of the vehicle with the inoperative mirror heating
grid. Unplug the wire harness connector at the mir-
ror. Check for continuity between the ground circuit
cavity in the body half of the power mirror wire har-
ness connector and a good ground. If OK, go to Step
4. If not OK, repair the open circuit to ground as
required.
(4) Connect the battery negative cable. Turn the
ignition switch to the On position. Turn on the rear
window defogger system. Check for battery voltage at
the rear window defogger relay output circuit cavity
in the body half of the power mirror wire harness
connector. If OK, go to Step 5. If not OK, repair the
open circuit to the rear window defogger relay as
required.
KJHEATED SYSTEMS 8G - 1

DIAGNOSIS AND TESTING - REAR WINDOW
DEFOGGER SYSTEM
For circuit descriptions and diagrams, (Refer to
Appropriate Wiring Information). The operation of
the electrically heated rear window defogger system
can be confirmed in one of the following manners:
²Turn the ignition switch to the run position.
²Set the defogger switch in the run position. The
rear window defogger operation can be checked by
feeling the rear window or outside rear view mirror
glass. A distinct difference in temperature between
the grid lines and the adjacent clear glass or the mir-
ror glass can be detected within three to four min-
utes of operation.
²Using a 12-volt DC voltmeter, contact the rear
glass heating grid terminal B (right side) with the
negative lead, and terminal A (left side) with the pos-
itive lead (Fig. 1). The voltmeter should read battery
voltage.
The above checks will confirm system operation.
Illumination of the defogger switch indicator lamp
means that there is electrical current available at the
output of the defogger relay, but does not confirmthat the electrical current is reaching the rear glass
heating grid lines.
If the defogger system does not operate, the prob-
lem should be isolated in the following manner:
(1) Confirm that the ignition switch is in the run
position.
(2) Ensure that the rear glass heating grid feed
and ground wires are connected to the glass. Confirm
that the ground wire has continuity to ground.
(3) Check the fuses in the Power Distribution Cen-
ter (PDC) and in the junction block. The fuses must
be tight in their receptacles and all electrical connec-
tions must be secure.
When the above steps have been completed and the
rear glass or outside rear view mirror heating grid is
still inoperative, one or more of the following is
faulty:
²Defogger switch
²Defogger relay
²HVAC control head circuitry
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)
²Outside rear view mirror heating grid.
If setting the defogger switch to the On position
produces a severe voltmeter deflection, check for a
short circuit between the defogger relay output and
the rear glass or outside rear view mirror heating
grids.
STANDARD PROCEDURE - REAR GLASS
HEATING GRID REPAIR
Repair of the rear glass heating grid lines, bus
bars, terminals or pigtail wires can be accomplished
using a Mopar Rear Window Defogger Repair Kit
(Part Number 4267922) or equivalent.
WARNING: MATERIALS CONTAINED IN THE REPAIR
KIT MAY CAUSE SKIN OR EYE IRRITATION. THE
KIT CONTAINS EPOXY RESIN AND AMINE TYPE
HARDENER, WHICH ARE HARMFUL IF SWAL-
LOWED. AVOID CONTACT WITH THE SKIN AND
EYES. FOR SKIN CONTACT, WASH THE AFFECTED
AREAS WITH SOAP AND WATER. FOR CONTACT
WITH THE EYES, FLUSH WITH PLENTY OF WATER.
DO NOT TAKE INTERNALLY. IF TAKEN INTER-
NALLY, INDUCE VOMITING AND CALL A PHYSICIAN
IMMEDIATELY. USE WITH ADEQUATE VENTILA-
TION. DO NOT USE NEAR FIRE OR FLAME. CON-
TAINS FLAMMABLE SOLVENTS. KEEP OUT OF THE
REACH OF CHILDREN.
(1) Mask the repair area so that the conductive
epoxy can be applied neatly. Extend the epoxy appli-
cation onto the grid line or the bus bar on each side
of the break (Fig. 2).
Fig. 1 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 - 4 WINDOW DEFOGGERKJ
WINDOW DEFOGGER (Continued)

(2) Follow the instructions in the repair kit for
preparing the damaged area.
(3) Remove the package separator clamp and mix
the two conductive epoxy components thoroughly
within the packaging. Fold the package in half and
cut the center corner to dispense the epoxy.
(4) For grid line repairs, mask the area to be
repaired with masking tape or a template.
(5) Apply the epoxy through the slit in the mask-
ing tape or template. Overlap both ends of the break
by at least 19 millimeters (0.75 inch).
(6) For a terminal or pigtail wire replacement,
mask the adjacent areas so the epoxy can be
extended onto the adjacent grid line as well as the
bus bar. Apply a thin layer of epoxy to the area
where the terminal or pigtail wire was fastened and
onto the adjacent grid line.
(7) Apply a thin layer of conductive epoxy to the
terminal or bare wire end of the pigtail and place it
in the proper location on the bus bar. To prevent the
terminal or pigtail wire from moving while the epoxy
is curing, it must be wedged or clamped.
(8)
Carefully remove the masking tape or template.
CAUTION: Do not allow the glass surface to exceed
204É C (400É F) or the glass may fracture.
(9) Allow the epoxy to cure 24 hours at room tem-
perature, or use a heat gun that will not over heat
the glass. Hold the heat gun approximately 25.4 cen-
timeters (10 inches) from the repair.
(10) After the conductive epoxy is properly cured,
remove the wedge or clamp from the terminal or pig-
tail wire. Do not attach the wire harness connectors
until the curing process is complete.
(11) Check the operation of the rear window defog-
ger glass heating grid.
REAR WINDOW DEFOGGER
GRID
DESCRIPTION
The heated rear window glass has two electrically
conductive vertical bus bars and a series of 11 hori-
zontal grid lines made of a silver-ceramic material,
which is baked on and bonded to the inside surface of
the glass. The grid lines and bus bars comprise a
parallel electrical circuit.
OPERATION
When the rear window defogger switch is placed in
the On position, electrical current is directed to the
rear window grid lines through the bus bars. The
grid lines heat the rear window to clear the surface
of fog or snow. Protection for the heated grid circuit
is provided by a fuse in the Power Distribution Cen-
ter (PDC).
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 clean-
ing the glass or removing foreign materials, decals,
or stickers from the glass. Normal glass cleaning sol-
vents or hot water used with rags or toweling is rec-
ommended.
A repair kit is available to repair the grid lines and
bus bars, or to reinstall the heated glass pigtail
wires.
DIAGNOSIS AND TESTING - REAR WINDOW
DEFOGGER GRID
For circuit descriptions and diagrams, (Refer to
Appropriate Wiring Information). To detect breaks in
the grid lines, the following procedure is required:
(1) Turn the ignition switch to the run position.
Set the defogger switch in the On position. The indi-
cator lamp should light. If OK, go to Step 2. If not
OK, (Refer to 8 - ELECTRICAL/HEATED GLASS/
REAR WINDOW DEFOGGER RELAY - DIAGNOSIS
AND TESTING)
(2) Using a 12-volt DC voltmeter, contact the ver-
tical bus bar on the right side of the vehicle with the
negative lead. With the positive lead, contact the ver-
tical bus bar on the left side of the vehicle. The volt-
meter should read battery voltage. If OK, go to Step
3. If not OK, repair the open circuit to the defogger
relay as required.
(3) With the negative lead of the voltmeter, contact
a good body ground point. The voltage reading should
not change. If OK, go to Step 4. If not OK, repair the
circuit to ground as required.
Fig. 2 GRID LINE REPAIR
1 - BREAK
2 - GRID LINE
3 - MASKING TAPE
KJWINDOW DEFOGGER 8G - 5
WINDOW DEFOGGER (Continued)

(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)

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 60.7 to 80.3 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, see the Relay Circuit Test in this
group. If not OK, replace the faulty relay.
30 - COMMON FEED
85 - COIL GROUND
86 - COIL BATTERY
87 - NORMALLY OPEN
87A - NORMALLY CLOSED
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 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.
(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 and outside rear view mirror heat-
ing grids and the defogger switch indicator lamp.
There should be continuity between the cavity for
relay terminal 87 and the rear window defogger relay
output circuit cavities of the rear glass heating grid
connector, both outside rear view mirror heating grid
connectors, and the defogger switch connector at all
times. If OK, go to Step 4. If not OK, repair the open
circuit(s) as required.(4) The coil ground terminal (85) is connected to
the electromagnet in the relay. This terminal is pro-
vided with ground by the instrument cluster rear
window defogger timer and logic circuitry to energize
the defogger relay. There should be continuity to
ground at the cavity for relay terminal 85 when the
defogger switch is turned On. However, with the
defogger relay removed, the defogger switch indicator
lamp will not light to show that the defogger system
is turned On. Be certain that you depress the defog-
ger switch at least twice to confirm that the system
is turned on during this test. If OK, go to Step 5. If
not OK, repair the open circuit to the HVAC control
head as required.
(5) The coil battery terminal (86) is connected to
the electromagnet in the relay. It is connected to
fused ignition switch output voltage and should be
hot when the ignition switch is in the run position.
Check for battery voltage at the cavity for relay ter-
minal 86 with the ignition switch in the run position.
If OK, see the diagnosis for Instrument Cluster in
this group. If not OK, repair the open circuit to the
fuse in the junction block 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) Unplug the rear window defogger relay from
the junction block.
INSTALLATION
(1) Install the rear window defogger relay by align-
ing the relay terminals with the cavities in the junc-
tion block and pushing the relay firmly into place.
(2) Connect the battery negative cable.
(3) Test the relay operation.
Fig. 4 DEFOGGER RELAY- TERMINAL LEGEND
KJWINDOW DEFOGGER 8G - 7
REAR WINDOW DEFOGGER RELAY (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

DIAGNOSIS AND TESTING - REAR HVAC
CONTROL ASSEMBLY WINDOW DEFOGGER
FUNCTION
Before performing this test, complete the Defogger
Switch and Defogger Relay tests as described in this
group. 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 defogger relay from the junction
block and unplug the defogger switch wire harness
connector.
(2) Remove the HVAC control head from the
instrument panel. This is accomplished by removing
the ashtray and the screw behind the ashtray and
uncliping the center bezel.
(3) Check for continuity between the rear window
defogger switch sense circuit cavity of the cluster
wire harness connector (connector B) and a good
ground. There should be no continuity. If OK, go to
Step 4. If not OK, repair the short circuit as
required.
(4) Check for continuity between the rear window
defogger switch sense circuit cavity of the right
instrument cluster wire harness connector (connector
B) and the defogger switch wire harness connector.
There should be continuity. If OK, go to Step 5. If not
OK, repair the open circuit as required.
(5) Check for continuity between the rear window
defogger relay control circuit cavity of the right
instrument cluster wire harness connector (connectorB) and a good ground. There should be no continuity.
If OK, go to Step 6. If not OK, repair the short circuit
as required.
(6) Check for continuity between the rear window
defogger relay control circuit cavities of the right
instrument cluster wire harness connector (connector
B) and the defogger relay receptacle (the cavity for
ISO relay terminal 85) in the junction block. There
should be continuity. If OK, replace the faulty HVAC
control head. If not OK, repair the open 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) The Rear Window Defogger switch is part of
the HVAC assembly and if damaged or inoperative
the entire HVAC control assembly must be replace-
d(Refer to 24 - HEATING & AIR CONDITIONING/
CONTROLS/A/C HEATER CONTROL - REMOVAL).
INSTALLATION
(1) The Rear Window Defogger switch is part of
the HVAC control assembly and if damaged or inop-
erative you must replace the entire HVEAC control
head assembly(Refer to 24 - HEATING & AIR CON-
DITIONING/CONTROLS/A/C HEATER CONTROL -
INSTALLATION).
(2) Connect the battery negative cable.
KJWINDOW DEFOGGER 8G - 9
REAR WINDOW DEFOGGER SWITCH (Continued)