2002 JEEP GRAND CHEROKEE Transmission harness

open circuit to the fuse in the junction block as
required.
(5) The coil ground terminal cavity (85) is switched
to ground through the Powertrain Control Module
(PCM). There should be continuity between this cav-
ity and the A/C compressor clutch relay control cir-
cuit cavity of the PCM wire harness connector C
(gray) at all times. If not OK, repair the open circuit
as required.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the cover from the Power Distribution
Center (PDC) (Fig. 11).
(3) Refer to the label on the PDC for compressor
clutch relay identification and location.
(4) Unplug the compressor clutch relay from the
PDC.
INSTALLATION
(1) Install the compressor clutch relay by aligning
the relay terminals with the cavities in the PDC and
pushing the relay firmly into place.
(2) Install the PDC cover.
(3) Connect the battery negative cable.
(4) Test the relay operation.
A/C HEATER CONTROL
DESCRIPTION
The manual temperature control HVAC system
uses a combination of electrical, and vacuum con-trols. The Automatic Zone Control (AZC) HVAC sys-
tem uses only electrical controls. These controls
provide the vehicle operator with a number of setting
options to help control the climate and comfort
within the vehicle. Refer to the owner's manual in
the vehicle glove box for more information on the
suggested operation and use of these controls.
Both a/c heater control panels are located on the
instrument panel inboard of the steering column and
below the radio (Fig. 12). Both control panels contain
rotary-type temperature control knob(s), a rotary-
type mode control switch knob, a rotary-type blower
motor speed switch knob and an air conditioning
compressor push button switch. The rear window
defogger push button switch is also located on a/c
heater control panel. The AZC control panel also fea-
tures a recirculation push button switch and a vac-
uum fluorescent display area.
OPERATION
The AZC control module uses infrared sensing
technology to control occupant comfort levels, not the
actual passenger compartment air temperature. Dual
infrared sensors mounted in the face of the control
unit independently measure the surface temperature
to maintain customer-perceived comfort temperature
under changing conditions. Dual Zone temperature
control provides wide side-to-side variation in comfort
temperature to exceed the needs of either front seat
occupant. This sensing system replaces interior air
temperature and solar sensors used to approximate
direct sensing control through complex control pro-
grams.
Fig. 11 POWER DISTRIBUTION CENTER (PDC)
1 - TRANSMISSION CONTROL MODULE (TCM)
2 - NEGATIVE CABLE
3 - POSITIVE CABLE
4 - POWER DISTRIBUTION CENTER (PDC)
Fig. 12 A/C HEATER CONTROL PANELS
WJCONTROLS 24 - 17
A/C COMPRESSOR CLUTCH RELAY (Continued)

BLEND DOOR ACTUATOR
DESCRIPTION
The blend door for all models is actuated by an
electric actuator, while the AZC system uses 2 sepa-
rate actuators to allow the driver and passenger to
select individual comfort levels. In the following pro-
cedures, service for both types of actuators is cov-
ered.
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.
The blend door actuator is used on all models,
whether equipped with manual or Automatic Zone
Control (AZC). This actuator is located on the front of
the HVAC housing to the right of the floor panel
transmission tunnel, and can be removed from the
passenger compartment without instrument panel or
HVAC housing removal.
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the glove box door. Refer to Instrument
Panel System for the procedures.
(3) Remove the lower I/P glove box door surround
panel. Refer to Instrument Panel System for the pro-
cedures.
(4) Unplug the wire harness connector from the
blend door actuator (Fig. 17).
(5) Remove the 2 screws that secure the blend
door actuator to the HVAC housing.
(6) Remove the blend door actuator from the
HVAC housing.
INSTALLATION
(1) Install the blend door actuator on the HVAC
housing and tighten the two mounting screws to 2.2
N´m (20 in. lbs.).
(2) Plug in the wire harness connector to the blend
door actuator.
(3) Install the glove box door. Refer to Instrument
Panel System for the procedures.
(4) Install the lower I/P glove box door surround
panel. Refer to Instrument Panel System for the pro-
cedures.
(5) Connect and the battery negative cable.
MODE DOOR ACTUATOR
DESCRIPTION
The mode door actuators for vehicles equipped with
the standard equipment manual temperature control
system are vacuum controlled. The optional Auto-
matic Zone Control (AZC) system uses electric motors
to actuate all mode doors. The service procedures for
both types of actuators are covered by the following
procedures.
Fig. 17 BLEND DOOR ACTUATOR
1 - BLEND DOOR ACTUATOR
2 - ELECTRICAL CONNECTOR
24 - 30 CONTROLSWJ

REMOVAL
REMOVAL - HEAT/DEFROST - PANEL/DEFROST
DOOR ELECTRIC ACTUATOR
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.
These actuators are used only on models equipped
with the optional Automatic Zone Control (AZC) sys-
tem.
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the two bolts that secure the center
instrument panel support bracket to the left side of
the floor panel transmission tunnel.
(3) Remove the two bolts that secure the center
instrument panel support bracket to the instrument
panel.
(4) Remove the center instrument panel support
bracket from the vehicle.
(5) Unplug the wire harness connector from the
heat/defrost - panel/defrost door actuator (Fig. 18).
(6) Remove the three screws that secure the heat/
defrost-panel/defrost door motor to the HVAC hous-
ing.
(7) Remove the heat/defrost-panel/defrost door
motor from the HVAC housing.
REMOVAL - HEAT/DEFROST DOOR VACUUM
ACTUATOR
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 PRECAU-
TIONS COULD RESULT IN AN ACCIDENTAL AIRBAG
DEPLOYMENT AND POSSIBLE PERSONAL INJURY.
This actuator is used only on models equipped with
the standard manual temperature control system.
(1) Remove the HVAC housing from the vehicle.
(Refer to 24 - HEATING & AIR CONDITIONING/
DISTRIBUTION/HVAC HOUSING - REMOVAL)
(2) Unplug the vacuum harness connector from the
heat/defrost door vacuum actuator (Fig. 19).
(3) Disengage the heat/defrost door pivot connec-
tion from the heat/defrost door pivot pin.
(4) Remove the screws that secure the heat/defrost
door vacuum actuator to the HVAC housing.
(5) Remove the heat/defrost door vacuum actuator
from the HVAC housing.
Fig. 18 HEAT/DEFROST - PANEL/DEFROST DOOR
ACTUATOR
1 - LEVER ASSEMBLY
2 - LINKAGE
3 - ELECTRIC ACTUATOR
WJCONTROLS 24 - 31
MODE DOOR ACTUATOR (Continued)

REMOVAL - PANEL/DEFROST DOOR VACUUM
ACTUATOR
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.
This actuator is used only on models equipped with
the standard manual temperature control system.
(1) Remove the HVAC housing from the vehicle.
(Refer to 24 - HEATING & AIR CONDITIONING/
DISTRIBUTION/HVAC HOUSING - REMOVAL)
(2) Unplug the vacuum harness connector from the
heat/defrost door vacuum actuator (Fig. 20).(3) Disengage the panel/defrost door pivot connec-
tion from the panel/defrost door pivot pin.
(4) Remove the screws that secure the panel/de-
frost door vacuum actuator to the HVAC housing.
(5) Remove the panel/defrost door vacuum actuator
from the HVAC housing.INSTALLATION
INSTALLATION - HEAT/DEFROST - PANEL/
DEFROST DOOR ELECTRIC ACTUATOR
(1) Install the heat/defrost-panel/defrost door
actuator on the HVAC housing, and tighten the three
mounting screws to 2.2 N´m (20 in. lbs.).
(2) Plug in the wire harness connector to the heat/
defrost - panel/defrost door actuator.
(3) Install the center instrument panel support
bracket on the vehicle.
(4) Install the two bolts that secure the center
instrument panel support bracket to the instrument
panel.
(5) Install the two bolts that secure the center
instrument panel support bracket to the left side of
the floor panel transmission tunnel.
(6) Connect the battery negative cable.
Fig. 19 MODE DOOR ACTUATORS-MANUAL
SYSTEM
1 - VACUUM LINES
2 - ACTUATING LEVERS
3 - LINKAGE
4 - VACUUM ACTUATORS
5 - ACTUATING LEVER
Fig. 20 PANEL/DEFROST DOOR ACTUATOR
1 - VACUUM LINE
2 - PANEL/DEFROST DOOR ACTUATOR
3 - SHAFT RETAINER
24 - 32 CONTROLSWJ
MODE DOOR ACTUATOR (Continued)

The high pressure relief valve vents only enough
refrigerant to reduce the system pressure, and then
re-seats itself. The majority of the refrigerant is con-
served in the system. If the valve vents refrigerant, it
does not mean that the valve is faulty.
The high pressure relief valve is a factory-cali-
brated unit. The valve cannot be adjusted or
repaired, and must not be removed or otherwise dis-
turbed. The valve is only serviced as a part of the
compressor assembly.
DIAGNOSIS AND TESTING - COMPRESSOR
NOISE
When investigating an air conditioning related
noise, you must first know the conditions under
which the noise occurs. These conditions include:
weather, vehicle speed, transmission in gear or neu-
tral, engine speed, engine temperature, and any
other special conditions. Noises that develop during
air conditioning operation can often be misleading.
For example: What sounds like a failed front bearing
or connecting rod, may be caused by loose bolts, nuts,
mounting brackets, or a loose compressor clutch
assembly.
Drive belts are speed sensitive. At different engine
speeds and depending upon belt tension, belts can
develop noises that are mistaken for a compressor
noise. Improper belt tension can cause a misleading
noise when the compressor clutch is engaged, which
may not occur when the compressor clutch is disen-
gaged. Check the serpentine drive belt condition and
tension as described in Cooling before beginning this
procedure.
(1) Select a quiet area for testing. Duplicate the
complaint conditions as much as possible. Switch the
compressor on and off several times to clearly iden-
tify the compressor noise. Listen to the compressor
while the clutch is engaged and disengaged. Probe
the compressor with an engine stethoscope or a long
screwdriver with the handle held to your ear to bet-
ter localize the source of the noise.
(2) Loosen all of the compressor mounting hard-
ware and retighten. Tighten the compressor clutch
mounting nut. Be certain that the clutch coil is
mounted securely to the compressor, and that the
clutch plate and pulley are properly aligned and have
the correct air gap. (Refer to 24 - HEATING & AIR
CONDITIONING/CONTROLS/A/C COMPRESSOR
CLUTCH - INSTALLATION)
(3) To duplicate a high-ambient temperature condi-
tion (high head pressure), restrict the air flow
through the condenser. Install a manifold gauge set
to be certain that the discharge pressure does not
exceed 2760 kPa (400 psi).
(4) Check the refrigerant system plumbing for
incorrect routing, rubbing or interference, which cancause unusual noises. Also check the refrigerant lines
for kinks or sharp bends that will restrict refrigerant
flow, which can cause noises. (Refer to 24 - HEAT-
ING & AIR CONDITIONING/PLUMBING - CAU-
TION - REFRIGERANT HOSES/LINES/TUBES
PRECAUTIONS)
(5) If the noise is from opening and closing of the
high pressure relief valve, reclaim, evacuate, and
recharge the refrigerant system. (Refer to 24 - HEAT-
ING & AIR CONDITIONING/PLUMBING - STAN-
DARD PROCEDURE - REFRIGERANT RECOVERY)
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - STANDARD PROCEDURE - REFRIG-
ERANT SYSTEM EVACUATE) (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
STANDARD PROCEDURE - REFRIGERANT SYS-
TEM CHARGE)If the high pressure relief valve still
does not seat properly, replace the a/c compressor.
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING/A/C COMPRESSOR - REMOVAL)
(6) If the noise is from liquid slugging on the suc-
tion line, check the refrigerant oil level and the
refrigerant system charge. (Refer to 24 - HEATING
& AIR CONDITIONING/PLUMBING/REFRIGER-
ANT OIL - STANDARD PROCEDURE) (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
SPECIFICATIONS - CHARGE CAPACITY).
(7) If the noise continues, replace the compressor
and repeat Step 1.
REMOVAL
REMOVAL
The compressor may be removed and repositioned
without disconnecting the refrigerant lines or dis-
charging the refrigerant system. Discharging is not
necessary if servicing the compressor clutch or clutch
coil, the engine, the cylinder head, or the generator.
WARNING: REVIEW THE WARNINGS AND CAU-
TIONS IN THE FRONT OF THIS SECTION BEFORE
PERFORMING THE FOLLOWING OPERATION.
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - WARNING) (Refer to 24 - HEATING &
AIR CONDITIONING/PLUMBING - CAUTION)
(1) Recover the refrigerant from the system. (Refer
to 24 - HEATING & AIR CONDITIONING/PLUMB-
ING - STANDARD PROCEDURE - REFRIGERANT
RECOVERY)
(2) Disconnect and isolate the battery negative
cable.
(3) Remove the serpentine drive belt. Refer to
Cooling for the procedures.
(4) Unplug the compressor clutch coil wire harness
connector.
24 - 58 PLUMBINGWJ
A/C COMPRESSOR (Continued)