2002 JEEP GRAND CHEROKEE Heating

STANDARD PROCEDURE
STANDARD PROCEDURE - FLUID LEVEL
CHECK
Low fluid level can cause a variety of conditions
because it allows the pump to take in air along with
the fluid. As in any hydraulic system, air bubbles
make the fluid spongy, therefore, pressures will be
low and build up slowly.
Improper filling can also raise the fluid level too
high. When the transmssion has too much fluid, the
geartrain churns up foam and cause the same condi-
tions which occur with a low fluid level.
In either case, air bubbles can cause overheating
and/or fluid oxidation, and varnishing. This can inter-
fere with normal valve, clutch, and accumulator opera-
tion. Foaming can also result in fluid escaping from the
transmission vent where it may be mistaken for a leak.
After the fluid has been checked, seat the dipstick
fully to seal out water and dirt.
The transmission has a dipstick to check oil level.
It is located on the right side of the engine. Be sure
to wipe all dirt from dipstick handle before removing.
The torque converter fills in both the P (PARK)
and N (NEUTRAL) positions. Place the selector lever
in P (PARK) to be sure that the fluid level check is
accurate.The engine should be running at idle
speed for at least one minute, with the vehicle
on level ground.At normal operating temperature(approximately 82 C. or 180 F.), the fluid level is cor-
rect if it is in the HOT region (cross-hatched area) on
the oil level indicator. The fluid level will be approx-
imately at the upper COLD hole of the dipstick at
70É F fluid temperature.
NOTE: Engine and Transmission should be at nor-
mal operating temperature before performing this
procedure.
(1) Start engine and apply parking brake.
(2) Shift the transmission into DRIVE for approxi-
mately 2 seconds.
(3) Shift the transmission into REVERSE for
approximately 2 seconds.
(4) Shift the transmission into PARK.
(5)
Hook up DRBtscan tool and select transmission.
(6) Select sensors.
(7) Read the transmission temperature value.
(8) Compare the fluid temperature value with the
chart. (Fig. 59)
(9) Adjust transmission fluid level shown on the
dipstick according to the chart.
NOTE: After adding any fluid to the transmission,
wait a minimum of 2 minutes for the oil to fully
drain from the fill tube into the transmission before
rechecking the fluid level.
(10) Check transmission for leaks.
Fig. 59 Transmission Fluid Temperature Chart
WJAUTOMATIC TRANSMISSION - 545RFE 21 - 229
FLUID AND FILTER (Continued)

SPARE TIRE
DESCRIPTION - SPARE / TEMPORARY TIRE
The temporary spare tire is designed for emer-
gency use only. The original tire should be repaired
or replaced at the first opportunity, then reinstalled.
Do not exceed speeds of 50 M.P.H. when using the
temporary spare tire. Refer to Owner's Manual for
complete details.
WHEELS
DESCRIPTION
The rim size is on the vehicle safety certification
label located on the drivers door shut face. The size
of the rim is determined by the drivetrain package.
Original equipment wheels/rims are designed for
operation up to the specified maximum vehicle capac-
ity.
All models use stamped steel, cast aluminum or
forged aluminum wheels. Every wheel has raised sec-
tions between the rim flanges and rim drop well
called safety humps (Fig. 18) .
Initial inflation of the tire forces the bead over
these raised sections. In case of rapid loss of air pres-
sure, the raised sections help hold the tire on the
wheel.
The wheel studs and nuts are designed for specific
applications. All aluminum and some steel wheels
have wheel stud nuts with an enlarged nose. This
enlarged nose is necessary to ensure proper retentionof the wheels. Do not use replacement studs or nuts
with a different design or lesser quality.
DIAGNOSIS AND TESTING - WHEEL
INSPECTION
Inspect wheels for:
²Excessive run out
²Dents or cracks
²Damaged wheel lug nut holes
²Air Leaks from any area or surface of the rim
NOTE: Do not attempt to repair a wheel by hammer-
ing, heating or welding.
If a wheel is damaged an original equipment
replacement wheel should be used. When obtaining
replacement wheels, they should be equivalent in
load carrying capacity. The diameter, width, offset,
pilot hole and bolt circle of the wheel should be the
same as the original wheel.
WARNING: FAILURE TO USE EQUIVALENT
REPLACEMENT WHEELS MAY ADVERSELY
AFFECT THE SAFETY AND HANDLING OF THE
VEHICLE. USED WHEELS ARE NOT RECOM-
MENDED. THE SERVICE HISTORY OF THE WHEEL
MAY HAVE INCLUDED SEVERE TREATMENT OR
VERY HIGH MILEAGE. THE RIM COULD FAIL WITH-
OUT WARNING.
STANDARD PROCEDURE - WHEEL
REPLACEMENT
The wheel studs and nuts are designed for specific
applications. They must be replaced with equivalent
parts. Do not use replacement parts of lesser quality
or a substitute design. All aluminum and some steel
wheels have wheel stud nuts which feature an
enlarged nose. This enlarged nose is necessary to
ensure proper retention of the aluminum wheels.
NOTE: Do not use chrome plated lug nuts with
chrome plated wheels.
Before installing the wheel, be sure to remove any
build up of corrosion on the wheel mounting surfaces.
Ensure wheels are installed with good metal-to-metal
contact. Improper installation could cause loosening
of wheel nuts. This could affect the safety and han-
dling of your vehicle.
To install the wheel, first position it properly on
the mounting surface. All wheel nuts should then be
tightened just snug. Gradually tighten them in
sequence to the proper torque specification.Never
use oil or grease on studs or nuts.
Wheels must be replaced if they have:
²Excessive runout
Fig. 18 Safety Rim
1 - FLANGE
2 - RIDGE
3 - WELL
22 - 10 TIRES/WHEELSWJ

²Bent or dented
²Leak air through welds
²Have damaged bolt holes
Wheel repairs employing hammering, heating, or
welding are not allowed.
Original equipment wheels are available through
your dealer. Replacement wheels from any other
source should be equivalent in:
²Load carrying capacity
²Diameter
²Width²Offset
²Mounting configuration
Failure to use equivalent replacement wheels may
affect the safety and handling of your vehicle.
Replacement withusedwheels is not recommended.
Their service history may have included severe treat-
ment.
SPECIFICATIONS
TORQUE CHART
TORQUE SPECIFICATIONS
DESCRIPTION N´m Ft. Lbs. In. Lbs.
Lug Nut
1/2 X 20 with 60É Cone115-150 85-115 Ð
STUDS
REMOVAL
CAUTION: Do not use a hammer to remove wheel
studs.
(1) Raise and support vehicle.
(2) Remove wheel and tire assembly.
(3) Remove brake caliper, caliper adapter and
rotor,(Refer to 5 - BRAKES/HYDRAULIC/MECHAN-
ICAL/ROTORS - REMOVAL).
(4) Remove stud from hub with Remover C-4150A
(Fig. 19).
INSTALLATION
CAUTION: Do not use a hammer to remove wheel
studs.
(1) Install the new stud into the hub flange.
(2) Install the three washers onto the stud, then
install the lug nut with the flat side of the nut
against the washers.
(3) Tighten the lug nut until the stud is pulled
into the hub flange. Verify that the stud is properly
seated into the flange.
(4) Remove the lug nut and washers.
(5) Install the brake rotor, caliper adapter, and
caliper,(Refer to 5 - BRAKES/HYDRAULIC/ME-
CHANICAL/DISC BRAKE CALIPERS - INSTALLA-
TION).(6) Install the wheel and tire assembly, use new
lug nut on stud or studs that were replaced.
(7) Remove the support and lower vehicle.Fig. 19 Wheel Stud Removal
1 - REMOVER
2 - WHEEL STUD
WJTIRES/WHEELS 22 - 11
WHEELS (Continued)

EXTERIOR NAME PLATES
REMOVAL
NOTE: Exterior nameplates are attached to body
panels with adhesive tape.
(1) Apply a length of masking tape on the body,
parallel to the top edge of the nameplate to use as a
guide, if necessary.
(2) If temperature is below 21ÉC (70ÉF) warm
emblem with a heat lamp or gun. Do not exceed 52ÉC
(120ÉF) when heating emblem.
(3) Insert a plastic trim stick or a hard wood
wedge behind the emblem to separate the adhesive
backing from the body.
(4) Clean adhesive residue from body with MOPAR
Super Clean solvent or equivalent.
INSTALLATION
(1) Remove protective cover from adhesive tape on
back of emblem.
(2) Position emblem properly on body.(3) Press emblem firmly to body with palm of
hand.
(4) If temperature is below 21ÉC (70ÉF) warm
emblem with a heat lamp or gun to assure adhesion.
Do not exceed 52ÉC (120ÉF) when heating emblem.
FRONT FENDER
REMOVAL
(1) Using a wax crayon or equivalent, mark posi-
tion of fender.
(2) Remove front fender liner.
(3) Pull back fascia and remove screws attaching
fender to fascia.
(4) Remove screws attaching lower fender bracket
located behind fascia.
(5) Remove screws attaching fender to rocker
panel (Fig. 6).
(6) Remove screws attaching rear of fender to
A-pillar brackets.
(7) Open hood.
Fig. 6 Fender Mounting
1 - BODY
2 - FENDER
23 - 28 EXTERIORWJ

(18) Remove the four nuts that secure the steering
column to the studs on the instrument panel steering
column support bracket.
(19) Remove the steering column from the instru-
ment panel. Be certain that the steering wheel is
locked and secured from rotation to prevent the loss
of clockspring centering.
(20) Disconnect the left and right body wire har-
ness connectors, the Ignition Off Draw (IOD) wire
harness connector and the fused B(+) wire harness
connector from the connector receptacles of the JB
(Fig. 5).(21) Disconnect the instrument panel wire harness
connectors from the following floor panel transmis-
sion tunnel components (Fig. 6):
²the Airbag Control Module (ACM) connector
receptacle
²the park brake switch terminal
²the transmission shifter connector receptacle.
(22) Remove the two nuts that secure the instru-
ment panel wire harness ground eyelets to the studs
on the floor panel transmission tunnel in front of and
behind the ACM.
(23) Disengage the retainers that secure the
instrument panel wire harness to the floor panel
transmission tunnel.
(24) Remove the instrument panel to center floor
tunnel bracket from the instrument panel and the
floor panel transmission tunnel. (Refer to 23 - BODY/
INSTRUMENT PANEL/IP CENTER FLOOR TUN-
NEL BRACKET - REMOVAL).
(25) Remove the one screw that secures the floor
duct to the heater and air conditioner housing near
the driver side of the floor panel transmission tunnel
and remove the duct from the housing.
(26) If the vehicle is equipped with the manual
heating and air conditioning system, disconnect the
vacuum harness connector located near the driver
side of the floor panel transmission tunnel behind
the driver side floor duct.
(27) Remove the one screw that secures the instru-
ment panel steering column support bracket to the
driver side end of the heater and air conditioner
housing (Fig. 7).
(28) Remove the one screw that secures the instru-
ment panel steering column support bracket to the
intermediate bracket on the driver side dash panel
(Fig. 8).
Fig. 5 Junction Block Connections
1 - SNAP CLIPS
2 - SCREW
3 - CONNECTOR
4 - LEFT BODY WIRE HARNESS
5 - IOD CONNECTOR
6 - FUSED B+ CONNECTOR
7 - RIGHT BODY WIRE HARNESS
8 - SCREW
9 - CONNECTOR
10 - JUNCTION BLOCK
WJINSTRUMENT PANEL SYSTEM 23 - 39
INSTRUMENT PANEL SYSTEM (Continued)

INSTALLATION
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 ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) Prior to installing the instrument panel into
the vehicle, loosen the three nuts that secure the
instrument panel intermediate bracket and the accel-
erator pedal assembly to the studs on the dash panel
(Fig. 8).
(2) With the aid of an assistant, load the instru-
ment panel assembly through the driver side front
door of the vehicle and hang it on the studs on the
dash panel near the windshield fence line (Fig. 1).
(3) Be certain that the molded plastic hook forma-
tions on the instrument panel structural duct are
inserted into and seated in the guide holes at each
cowl side inner panel.
(4) Loosely install the two screws that secure each
end of the instrument panel to the cowl side inner
panels.
(5) Install and tighten the two screws that secure
the passenger side instrument panel structural duct
to the heater and air conditioner housing (Fig. 13).
Tighten the screws to 11.8 N´m (105 in. lbs.).
(6) Install and tighten the one screw that secures
the instrument panel steering column support
bracket to the driver side end of the heater and air
conditioner housing (Fig. 7). Tighten the screw to
11.8 N´m (105 in. lbs.).
(7) Tighten the two screws that secure each end of
the instrument panel to the cowl side inner panels
(Fig. 10) and (Fig. 14). Tighten the screws to 11.8
N´m (105 in. lbs.).
(8) Install and tighten the one screw that secures
the instrument panel steering column support
bracket to the intermediate bracket on the driver
side dash panel (Fig. 8). Tighten the screw to 11.3
N´m (100 in. lbs.).
(9) Tighten the three nuts that secure the instru-
ment panel intermediate bracket and the accelerator
pedal assembly to the studs on the dash panel.
Tighten the nuts to 11.3 N´m (100 in. lbs.).(10) Install and tighten the four nuts that secure
the instrument panel to the studs on the dash panel
near the windshield fence line. Tighten the nuts to
11.8 N´m (105 in. lbs.).
(11) Install and tighten the nut that secures the
instrument panel steering column support bracket to
the stud on the driver side cowl plenum panel (Fig.
9). Tighten the nut to 28.2 N´m (250 in. lbs.).
(12) Reinstall the instrument panel to center floor
tunnel bracket onto the instrument panel and the
floor panel transmission tunnel. (Refer to 23 - BODY/
INSTRUMENT PANEL/IP CENTER FLOOR TUN-
NEL BRACKET - INSTALLATION).
(13) Reconnect the two instrument panel wire har-
ness connectors to the two heater and air conditioner
housing connectors located near the blower motor on
the passenger side end of the housing (Fig. 12).
(14) Reconnect the two halves of the radio antenna
coaxial cable connector near the right cowl side inner
panel under the end of the instrument panel.
(15) Reconnect the instrument panel wire harness
connector to the lower cavity of the inline connector
on the passenger side cowl side inner panel and
tighten the connector screw (Fig. 11). Tighten the
screw to 4 N´m (36 in. lbs.).
(16) Reinstall the lower right center bezel onto the
instrument panel. (Refer to 23 - BODY/INSTRU-
MENT PANEL/IP LOWER RIGHT CENTER BEZEL
- INSTALLATION).
(17) Reinstall the end cap onto the instrument
panel. (Refer to 23 - BODY/INSTRUMENT PANEL/
INSTRUMENT PANEL END CAP - INSTALLA-
TION).
(18) If the vehicle is equipped with the manual
heating and air conditioning system, reconnect the
vacuum harness connector located near the driver
side of the floor panel transmission tunnel behind
the driver side floor duct.
(19) Position the driver side floor duct to the
heater and air conditioner housing near the driver
side of the floor panel transmission tunnel (Fig. 7).
(20) Install and tighten the one screw that secures
the driver side floor duct to the heater and air con-
ditioner housing near the driver side of the floor
panel transmission tunnel. Tighten the screw to 2.2
N´m (20 in. lbs.).
(21) Route the instrument panel wire harness to
the floor panel transmission tunnel and engage the
retainers that secure the harness to the mounting
brackets on the tunnel (Fig. 6).
(22) Install the instrument panel wire harness
ground eyelets to the studs on the floor panel trans-
mission tunnel in front of and behind the airbag con-
trol module and secure the eyelets with nuts. Tighten
the nuts to 7.3 N´m (65 in. lbs.).
WJINSTRUMENT PANEL SYSTEM 23 - 43
INSTRUMENT PANEL SYSTEM (Continued)

(22) Remove the front bin from the floor console.
(Refer to 23 - BODY/INTERIOR/FLOOR CONSOLE -
REMOVAL).
(23) Reach through the front bin opening of the
floor console to access and remove the two screws
that secure the center floor tunnel bracket to the
instrument panel.
(24) Reach through the front bin opening of the
floor console to access and loosen the two nuts that
secure the center floor tunnel bracket to the studs on
the floor panel transmission tunnel.
(25) Slide the center floor tunnel bracket rearward
in the vehicle far enough to disengage the locating
hole in the lower flange of the top pad from the locat-
ing pin on the instrument panel structural duct (Fig.
25).
(26) Remove the instrument panel top pad from
the instrument panel structural duct.INSTALLATION
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 ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
If the top pad is being replaced with a new unit, be
certain to transfer or install the panel outlets and
the passenger side trim bezel to the new unit before
it is installed on the instrument panel structural
duct. (Refer to 24 - HEATING & AIR CONDITION-
ING/DISTRIBUTION/AIR OUTLETS - REMOVAL)
and (Refer to 23 - BODY/INSTRUMENT PANEL/IP
TRIM BEZEL - PASSENGER - REMOVAL).
(1) Position the instrument panel top pad over the
instrument panel structural duct and the studs on
the dash panel near the windshield fence line.
(2) Route the instrument panel wire harness take
out for the glove box lamp and switch unit to the
switch mounting hole in the upper glove box opening
reinforcement.
(3) Reach through the front bin opening of the
floor console to engage the locating hole in the lower
flange of the top pad with the locating pin on the
instrument panel structural duct (Fig. 25).
(4) Reach through the front bin opening of the
floor console to slide the center floor tunnel bracket
forward in the vehicle far enough to capture the
lower flange of the top pad between the bracket and
the structural duct.
(5) Reach through the front bin opening of the
floor console to install and tighten the two screws
that secure the center floor tunnel bracket to the
instrument panel. Tighten the screws to 11.8 N´m
(105 in. lbs.).
Fig. 25 Instrument Panel Top Pad Remove/Install
1 - STRUCTURAL DUCT
2 - LOCATING PIN
3 - INSTRUMENT PANEL TOP PAD
4 - LOWER FLANGE
5 - CENTER FLOOR TUNNEL BRACKET
23 - 54 INSTRUMENT PANEL SYSTEMWJ
INSTRUMENT PANEL TOP PAD (Continued)

HEATING & AIR CONDITIONING
TABLE OF CONTENTS
page page
HEATING & AIR CONDITIONING
DESCRIPTION
DESCRIPTION - COOLING SYSTEM
REQUIREMENTS.......................1
DESCRIPTION - HEATER AND AIR
CONDITIONER........................1
DESCRIPTION - REFRIGERANT SYSTEM
SERVICE PORT........................1
OPERATION
OPERATION - HEATER AND AIR
CONDITIONER........................2
OPERATION - REFRIGERANT SYSTEM
SERVICE PORT........................2DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - A/C
PERFORMANCE.......................2
DIAGNOSIS AND TESTING - HEATER
PERFORMANCE.......................6
STANDARD PROCEDURE - DIODE
REPLACEMENT.......................6
SPECIFICATIONS
A/C APPLICATION TABLE................7
TORQUE SPECIFICATIONS..............8
CONTROLS.............................9
DISTRIBUTION..........................36
PLUMBING.............................51
HEATING & AIR
CONDITIONING
DESCRIPTION
DESCRIPTION - COOLING SYSTEM
REQUIREMENTS
To maintain the performance level of the heating-
air conditioning system, the engine cooling system
must be properly maintained. The use of a bug
screen is not recommended. Any obstructions in front
of the radiator or condenser will reduce the perfor-
mance of the air conditioning and engine cooling sys-
tems.
The engine cooling system includes the heater core
and the heater hoses. Refer to Cooling for more infor-
mation before opening, or attempting any service to
the engine cooling system.
DESCRIPTION - HEATER AND AIR
CONDITIONER
A manual temperature control type heating-air
conditioning system is standard factory-installed
equipment on this model. An electronically controlled
Automatic Zone Control (AZC) type heating-air con-
ditioning system is an available factory-installed
option.
All vehicles are equipped with a common HVAC
housing assembly (Fig. 1). The system combines air
conditioning, heating, and ventilating capabilities in
a single unit housing mounted under the instrument
panel.DESCRIPTION - REFRIGERANT SYSTEM
SERVICE PORT
The two refrigerant system service ports are used
to charge, recover/recycle, evacuate, and test the air
conditioning refrigerant system. Unique service port
coupler sizes are used on the R-134a system to
ensure that the refrigerant system is not accidentally
contaminated by the use of the wrong refrigerant
(R-12), or refrigerant system service equipment.
Fig. 1 Blend-Air HVAC System - (typical)
1 - Blend Door
2 - Expansion Valve
3 - Evaporator Core
4 - Blower Assembly
5 - Recirculation Door
6 - Evaporator Probe
7 - Heater Core
8 - Heat/Defrost Door
9 - Panel/Defrost Door
WJHEATING & AIR CONDITIONING 24 - 1