2002 JEEP GRAND CHEROKEE Abs

INSTALLATION
NOTE: Sunroof glass must be set in place and
attached as close as possible to flush with the roof
surface. For wind noise reasons, care must be
taken to ensure that the glass is not remounted
either a) Overflush to the roof surface at the front
edge of the glass, or b) Underflush to the roof sur-
face at the rear edge of the glass.
(1) Position glass panel in to opening.
(2) Start the four attaching screws.
(3) Tighten screws.
(4) Verify sunroof operation and alignment. Check
fit and adjust as necessary. (Refer to 23 - BODY/
SUNROOF/GLASS PANEL - ADJUSTMENTS - FIT)
ADJUSTMENTS
ADJUSTMENTS - FIT
(1) Move the sunshade rearward to the open posi-
tion.
(2) Move the sunroof glass panel to the fully closed
position.
(3) Loosen the forward screws on each side enough
to make the front adjustment.
(4) Adjust the front of the sunroof glass panel 1
mm (1/32 inch) below the top surface of the roof
panel.
(5) Tighten the front two screws.
(6) Loosen the rear screws on each side enough to
make the rear adjustment.
(7) Adjust the rear of the sunroof glass panel 1
mm (1/32 inch) above the top surface of the roof
panel.
(8) Tighten the rear two screws.
(9) Check for proper fit. If not OK, repeat glass
panel adjustment.
ADJUSTMENT - TIMING
NOTE: A gage comes with the new motor.
(1) If the glass panel was not in the fully closed
position, when the motor was removed, the sunroof
glass panel needs to be timed, before the new motor
is installed.
(2) Remove sunroof glass panel.
(3) Set gage into the track near the rear of the
opening between the driver slide and the bracket
(Fig. 6).
(4) Move the driver slide forward or aft to get
proper setting.
(5) Repeat the operation on the other side.
(6) Install drive motor.
SUNSHADE
REMOVAL
(1) Open sunroof approximately 50% of the way.
(2) Push sunshade down until tabs clear glass.
(3) Move sunshade forward of glass panel.
(4) Compress the spring loaded plungers holding
the guide blocks in the track.
(5) Slide the sunshade forward while lifting the
front through the opening until the rear guide blocks
are accessible.
CAUTION: Use care not to crease the sunshade
when removing or installing.
(6) Disengage rear guide blocks from track.
INSTALLATION
(1) Install the sunshade from outside of the vehicle
with the sunroof fully open.
(2) Put rear guide blocks into sunshade guide
track.
(3) Push sunshade back and down through the
sunroof opening.
(4) Using a flat blade tool, put front guide blocks
into the sunshade track. By pushing the block
towards the center of the vehicle.
(5) Move the glass panel to approximately halfway
to the fully closed position.
Fig. 6 Sunroof Drive Cable Timing
1 - MOVE DRIVER SLIDE FORWARD/AFT
2 - GAGE
WJSUNROOF 23 - 103
GLASS PANEL (Continued)

OPERATION
OPERATION - HEATER AND AIR CONDITIONER
Outside fresh air enters the vehicle through the
cowl top opening at the base of the windshield, and
passes through a plenum chamber to the HVAC sys-
tem blower housing. Air flow velocity can then be
adjusted with the blower motor speed selector switch
on the a/c heater control panel. The air intake open-
ings must be kept free of snow, ice, leaves, and other
obstructions for the HVAC system to receive a suffi-
cient volume of outside air.
It is also important to keep the air intake openings
clear of debris because leaf particles and other debris
that is small enough to pass through the cowl ple-
num screen can accumulate within the HVAC hous-
ing. The closed, warm, damp and dark environment
created within the HVAC housing is ideal for the
growth of certain molds, mildews and other fungi.
Any accumulation of decaying plant matter provides
an additional food source for fungal spores, which
enter the housing with the fresh air. Excess debris,
as well as objectionable odors created by decaying
plant matter and growing fungi can be discharged
into the passenger compartment during HVAC sys-
tem operation.
Both the manual and AZC heater and air condi-
tioner are blend-air type systems. In a blend-air sys-
tem, a blend door controls the amount of
unconditioned air (or cooled air from the evaporator)
that is allowed to flow through, or around, the heater
core. A temperature control knob on the a/c heater
control panel determines the discharge air tempera-
ture by energizing the blend door actuator, which
operates the blend door. This allows an almost imme-
diate control of the output air temperature of the sys-
tem. The AZC system will have separate blend doors
and temperature controls for each front seat occu-
pant.
The mode control knob on the a/c heater control
panel is used to direct the conditioned air to the
selected system outlets. On manual temperature con-
trol systems, the mode control knob switches engine
vacuum to control the mode doors, which are oper-
ated by vacuum actuators. On AZC systems, the
mode control knob switches electrical current to con-
trol the mode doors, which are operated by electronic
actuators.
The outside air intake can be shut off on manual
temperature control systems by selecting the Recircu-
lation Mode with the mode control knob. The outside
air intake can be shut off on Automatic Zone Control
(AZC) type system by pushing the Recirculation
Mode button. This will operate the recirculation door
that closes off the outside fresh air intake and recir-
culates the air that is already inside the vehicle.The air conditioner for all models is designed for
the use of non-CFC, R-134a refrigerant. The air con-
ditioning system has an evaporator to cool and dehu-
midify the incoming air prior to blending it with the
heated air. This air conditioning system uses a ther-
mal expansion valve to meter refrigerant flow to the
evaporator coil. To maintain minimum evaporator
temperature and prevent evaporator freezing, the
system utilizes an evaporator thermister probe with
the appropriate operating logic located in the body
control module (BCM).
OPERATION - REFRIGERANT SYSTEM SERVICE
PORT
The high pressure service port is located on the liq-
uid line near the receiver/drier. The low pressure ser-
vice port is located on the suction line near the
evaporator at the rear of the engine compartment.
Each of the service ports has a threaded plastic
protective cap installed over it from the factory. After
servicing the refrigerant system, always reinstall
both of the service port caps.
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - A/C
PERFORMANCE
The air conditioning system is designed to provide
the passenger compartment with low temperature
and low specific humidity air. The evaporator, located
in the HVAC housing on the dash panel below the
instrument panel, is cooled to temperatures near the
freezing point. As warm damp air passes through the
cooled evaporator, the air transfers its heat to the
refrigerant in the evaporator and the moisture in the
air condenses on the evaporator fins. During periods
of high heat and humidity, an air conditioning sys-
tem will be more effective in the Recirculation Mode.
With the system in the Recirculation Mode, only air
from the passenger compartment passes through the
evaporator. As the passenger compartment air dehu-
midifies, the air conditioning system performance
levels improve.
Humidity has an important bearing on the tempera-
ture of the air delivered to the interior of the vehicle. It
is important to understand the effect that humidity has
on the performance of the air conditioning system.
When humidity is high, the evaporator has to perform a
double duty. It must lower the air temperature, and it
must lower the temperature of the moisture in the air
that condenses on the evaporator fins. Condensing the
moisture in the air transfers heat energy into the evap-
orator fins and tubing. This reduces the amount of heat
the evaporator can absorb from the air. High humidity
greatly reduces the ability of the evaporator to lower
the temperature of the air.
24 - 2 HEATING & AIR CONDITIONINGWJ
HEATING & AIR CONDITIONING (Continued)

INSTALLATION
(1) Plug the wire harness and/or vacuum harness
connectors into the back of the a/c heater control.
(2) Position the a/c heater control in the instru-
ment panel and secure it with 4 screws. Tighten the
screws to 2.2 N´m (20 in. lbs.).
(3) Reinstall the center upper, and center lower
bezels onto the instrument panel. Refer to Instru-
ment Panel System for the procedures.
(4) Connect the battery negative cable.
A/C PRESSURE TRANSDUCER
DESCRIPTION
The A/C pressure transducer is installed on a fit-
ting located on the refrigerant discharge line near
the condenser. An internally threaded hex fitting on
the transducer connects it to the externally threaded
Schrader-type fitting on the discharge line. A rubber
O-ring seals the connection between the transducer
and the discharge line fitting. Three terminals within
a molded plastic connector receptacle on the top of
the transducer connect it to the vehicle electrical sys-
tem through a take out and connector of the head-
lamp and dash wire harness.
The A/C pressure transducer cannot be adjusted or
repaired and if faulty or damaged, it must be
replaced.
OPERATION
The A/C pressure transducer monitors the pres-
sures in the high side of the refrigerant system
through its connection to a fitting on the discharge
line. The transducer will change its internal resis-
tance in response to the pressures it monitors. The
Powertrain Control Module (PCM) provides a five
volt reference signal and a sensor ground to the
transducer, then monitors the output voltage of the
transducer on a sensor return circuit to determine
refrigerant pressure. The PCM is preporgrammed to
respond to this and other sensor inputs by controlling
the operation of the air conditioning compressor
clutch and the radiator cooling fan to help optimize
air conditioning system performance and to protect
the system components from damage. The A/C pres-
sure transducer input to the PCM will also prevent
the air conditioning compressor clutch from engaging
when the ambient temperatures are below about
0.556É C (33É F) due to the pressure/temperature
relationship of the refrigerant. The Schrader-type
valve in the liquid line fitting permits the A/C pres-
sure transducer to be removed or installed without
distrubing the refrigerant in the system. The A/C
pressure transducer is diagnosed using the DRBIIIt
scan tool. Refer to the appropriate diagnostic infor-
mation.
Fig. 13 A/C HEATER CONTROL REMOVE/INSTALL
1 - MOUNTING SCREW TABS
Fig. 14 A/C HEATER CONTROL CONNECTIONS
1 - MODE SWITCH
2 - ELECTRICAL CONNECTIONS
3 - VACUUM HARNESS
WJCONTROLS 24 - 25
A/C HEATER CONTROL (Continued)

INSTALLATION
(1) Install the defroster duct on the HVAC unit
housing.
(2) Install the three screws that secure the
defroster duct to the HVAC unit housing. Tighten the
mounting screws to 2.2 N´m (20 in. lbs.).
(3) Install the instrument panel assembly in the
vehicle(Refer to 23 - BODY/INSTRUMENT PANEL -
INSTALLATION).
FLOOR DISTRIBUTION DUCTS
REMOVAL
(1) To remove the driver side floor duct from the
vehicle, remove the knee blocker panel for access to
attaching screw. See Instrument Panel System for
the procedures.
(2) The passenger side floor duct fastener can be
accessed under the right-center instrument panel.
(3) Remove the screw that secures the floor duct(s)
to the HVAC housing (Fig. 5).
INSTALLATION
(1) Attach the floor duct(s) to the HVAC housing.
(2) Install the screw that secures the floor duct(s)
to the HVAC housing. Tighten the mounting screws
to 2.2 N´m (20 in. lbs.).
(3) Install the knee blocker panel. See Instrument
Panel System for the procedures.
INSTRUMENT PANEL DUCTS
REMOVAL
(1) Remove the instrument panel top pad from the
vehicle(Refer to 23 - BODY/INSTRUMENT PANEL/
INSTRUMENT PANEL TOP COVER - REMOVAL).
(2) Unsnap the duct extension(s) from the instru-
ment panel structural duct assembly (Fig. 6).
(3) Remove the duct extension(s) from the instru-
ment panel (Fig. 7).
INSTALLATION
(1) Connect the duct extension(s) to the instru-
ment panel.
(2) Snap the duct extension(s) to the instrument
panel structural duct assembly.
(3) Install the instrument panel top pad in the
vehicle(Refer to 23 - BODY/INSTRUMENT PANEL/
INSTRUMENT PANEL TOP COVER - INSTALLA-
TION).
REAR FLOOR HEAT DUCT
REMOVAL
(1) To remove the rear floor ducts from the vehicle,
remove the knee blocker panels for access, and pull
carpeting back.
(2) Pull the floor ducts from the HVAC housing
(Fig. 8).
NOTE: The ductwork running from the HVAC hous-
ing rearward through the passenger compartment is
molded into the carpeting, and must be replaced as
a unit if damaged.
INSTALLATION
(1) Attach the floor ducts to the HVAC housing.
(2) Install the knee blocker panels.
(3) Install the carpeting back in its original posi-
tion.
Fig. 5 FLOOR DUCTS (HOUSING REMOVED)
1 - FLOOR DUCT ADAPTER
2 - HEAT/DEFROST DOOR SUB-ASSEMBLY
3 - DOOR LEVERS
4 - LOWER HOUSING
5 - FLOOR DUCTS
6 - LINKAGE
7 - RETAINING TABS
WJDISTRIBUTION 24 - 39
DEFROSTER DUCTS (Continued)

STANDARD PROCEDURE - REFRIGERANT SYS-
TEM EVACUATE)
(13) Charge the refrigerant system. (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
STANDARD PROCEDURE - REFRIGERANT SYS-
TEM CHARGE)
(14) Install the instrument panel in the vehicle(Re-
fer to 23 - BODY/INSTRUMENT PANEL - INSTAL-
LATION).
(15) Connect the battery negative cable.
(16) Start the engine and check for proper opera-
tion of the heating and air conditioning systems.
BLEND DOOR
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) Remove and disassemble the HVAC housing.
(Refer to 24 - HEATING & AIR CONDITIONING/
DISTRIBUTION/HVAC HOUSING - REMOVAL)
(Refer to 24 - HEATING & AIR CONDITIONING/
DISTRIBUTION/HVAC HOUSING - DISASSEMBLY)
(2) Remove evaporator from lower case to ease
access to plastic door shaft bushing.
(3) Pinch the retention tabs holding the blend door
pivot shaft to the case. The 3 plastic tabs, located on
the inside of the case, are part of the shaft retainer.
(4) Remove door(s).
INSTALLATION
(1) Install the blend door(s) by snapping the pivot
shaft into the HVAC case.
(2) Install the evaporator in the lower case.
(3) Reassemble the HVAC housing and install in
the vehicle. (Refer to 24 - HEATING & AIR CONDI-
TIONING/DISTRIBUTION/HVAC HOUSING -
ASSEMBLY) (Refer to 24 - HEATING & AIR CON-
DITIONING/DISTRIBUTION/HVAC HOUSING -
INSTALLATION)NOTE: The blend door sub-assembly is attached to
the housing with 2 screws, and may be removed for
service (Fig. 20).
MODE DOOR
REMOVAL
REMOVAL - PANEL OUTLET DOOR
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) Remove and disassemble the HVAC housing.
(Refer to 24 - HEATING & AIR CONDITIONING/
DISTRIBUTION/HVAC HOUSING - REMOVAL)
(Refer to 24 - HEATING & AIR CONDITIONING/
DISTRIBUTION/HVAC HOUSING - DISASSEMBLY)
Fig. 20 BLEND DOOR SUB-ASSEMBLY
1 - PASSENGER SIDE BLEND DOOR
2 - BLEND DOOR SUB-ASSEMBLY
3 - DOOR PIVOT SHAFT BUSHING
4 - DOOR SHAFT LEVER
5 - DRIVER SIDE BLEND DOOR
24 - 46 DISTRIBUTIONWJ
HVAC HOUSING (Continued)

(2) Pinch the retention tabs holding the panel out-
let door pivot shaft to the case. The 3 plastic tabs,
located on the inside of the case, are part of the shaft
retainer (Fig. 21).
(3) Using a trim stick or another suitable wide
flat-bladed tool, gently pry the panel outlet door pivot
shaft retainer from the pivot shaft.
(4) Remove the panel outlet door from the HVAC
housing.
REMOVAL - HEAT/DEFROST DOOR
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) Remove and disassemble the HVAC housing.
(Refer to 24 - HEATING & AIR CONDITIONING/
DISTRIBUTION/HVAC HOUSING - REMOVAL)
(Refer to 24 - HEATING & AIR CONDITIONING/
DISTRIBUTION/HVAC HOUSING - DISASSEMBLY)
(2) Remove the evaporator, and styrofoam tray
from the lower case.
(3) Place the HVAC housing upside down on a
work bench.
(4) Unscrew and remove the 2 floor heat ducts.
(5) Unsnap and remove the duct adapter from the
bottom of the heat/defrost door sub-assembly (Fig.
22).
(6) Gently pry the metal linkage from the heat/de-
frost door lever.
(7) Remove the heat/defrost door sub-assembly,
which is attached to the housing with 4 screws (Fig.
23).
(8) Pinch the retention tabs holding the heat/de-
frost door pivot shaft lever to the case. The 3 plastic
tabs, located on the inside of the case, are part of the
shaft retainer.
(9) Remove the heat/defrost door (Fig. 24).
Fig. 21 PANEL OUTLET DOOR
1 - PANEL/OUTLET DOOR
2 - DOOR SHAFT
3 - FOAM SEAL
(SPLIT)
4 - LOWER HOUSING
5 - PANEL OUTLET DOOR LEVER
6 - LEVER
Fig. 22 HEAT/DEFROST DOOR DUCTS, AND
ADAPTER
1 - FLOOR DUCT ADAPTER
2 - HEAT/DEFROST DOOR SUB-ASSEMBLY
3 - DOOR LEVERS
4 - LOWER HOUSING
5 - FLOOR DUCTS
6 - LINKAGE
7 - RETAINING TABS
WJDISTRIBUTION 24 - 47
MODE DOOR (Continued)

REMOVAL - PANEL/DEFROST DOOR
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) Remove and disassemble the HVAC housing.
See HVAC Housing in this group for the procedures.
(2) Pinch the retention tabs holding the panel/de-
frost door pivot shaft to the case. The 3 plastic tabs,
located on the inside of the case, are part of the shaft
retainer (Fig. 25).
(3) Using a trim stick or another suitable wide
flat-bladed tool, gently pry the panel/defrost door
pivot shaft retainer from the pivot shaft.
(4) Remove the panel/defrost door from the HVAC
housing.
Fig. 23 HEAT/DEFROST DOOR SUB-ASSEMBLY
REMOVAL
1 - HEAT/DEFROST DOOR SUB-ASSEMBLY
2 - LEVERS
3 - LOWER HOUSING
4 - SCREWS
5 - LINKAGE
Fig. 24 HEAT/DEFROST DOOR REMOVAL
1 - HEAT/DEFROST DOOR
2 - LOWER HOUSING
3 - HEAT/DEFROST DOOR SUB-ASSEMBLY
4 - FLOOR DUCTS
5 - DOOR LEVER
Fig. 25 PANEL/DEFROST DOOR
1 - UPPER HOUSING
2 - LEVER
3 - PANEL/DEFROST MODE DOOR
24 - 48 DISTRIBUTIONWJ
MODE DOOR (Continued)

(5) Raise the front of the door sub-assembly while
releasing the 2 tabs holding the rear to the main
housing, and remove the recirculation door housing.
(6) Remove the electric/vacuum actuator from the
recirculation door sub-assembly and set aside.
(7) Pinch the retention tabs holding the recircula-
tion door pivot shaft to the case. The 3 plastic tabs,
located on the inside of the case, are part of the shaft
retainer.
(8) Remove the recirculation door from the recircu-
lation air door housing.
INSTALLATION
(1) Install the recirculation door in the recircula-
tion air door housing by snapping the pivot shaft
retention tabs into the case.
(2) Install the electric/vacuum actuator on the
recirculation door sub-assembly. Check door for bind-
ing after replacement.
(3) Install the recirculation door housing on the
HVAC case and tighten the 2 screws to 2.2 N´m (20
in. lbs.).
(4) Plug in the wire/vacuum connector to the recir-
culation door actuator.
(5) Install the HVAC housing in the vehicle. (Refer
to 24 - HEATING & AIR CONDITIONING/DISTRI-
BUTION/HVAC HOUSING - INSTALLATION)
24 - 50 DISTRIBUTIONWJ
RECIRCULATION DOOR (Continued)