2003 JEEP GRAND CHEROKEE glove box

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

BLOWER MOTOR
DESCRIPTION
The blower motor and blower wheel are located in
the passenger side end of the HVAC housing, below
the glove box module. The blower motor controls the
velocity of the air flowing through the HVAC housing
by spinning a squirrel cage-type blower wheel within
the housing at the selected speed. The blower motor
and blower wheel can be serviced from the passenger
compartment side of the housing.
OPERATION
The blower motor will only operate when the igni-
tion switch is in the On position, and the a/c heater
mode control switch is in any position, except off. The
blower motor circuit is protected by a fuse in the
junction block. On models with the standard manual
temperature control system, the blower motor speed
is controlled by regulating the battery feed through
the blower motor switch and the blower motor resis-
tor. On models with the optional Automatic Zone
Control (AZC) system, the blower motor speed is con-
trolled by using Pulse Width Modulation (PWM). The
blower motor controller adjusts the battery feed volt-
age to the blower motor, based upon an input from
the blower motor switch, through the AZC control
module. Pulse width modulation of blower power
allows the blower to operate at any speed from sta-
tionary, to full speed.
The blower motor and blower motor wheel cannot
be repaired, and if faulty or damaged, they must be
replaced. The blower motor and blower wheel are
each serviced separately.
DIAGNOSIS AND TESTING - BLOWER MOTOR
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.
For circuit descriptions and diagrams, refer to the
appropriate wiring information. Possible causes of an
inoperative blower motor include:
²Faulty fuse²Faulty blower motor circuit wiring or wire har-
ness connections
²Faulty blower motor resistor (if the vehicle is so
equipped)
²Faulty blower motor controller (if the vehicle is
so equipped)
²Faulty blower motor switch
²Faulty a/c heater mode control switch
²Faulty blower motor.
Possible causes of the blower motor not operating
in all speeds include:
²Faulty fuse
²Faulty blower motor switch
²Faulty blower motor resistor (if the vehicle is so
equipped)
²Faulty blower motor controller (if the vehicle is
so equipped)
²Faulty AZC module (if the vehicle is so
equipped)
²Faulty blower motor circuit wiring or wire har-
ness connections.
VIBRATION
Possible causes of blower motor vibration include:
²Improper blower motor mounting
²Improper blower wheel mounting
²Blower wheel out of balance or bent
²Blower motor faulty.
NOISE
To verify that the blower is the source of the noise,
unplug the blower motor wire harness connector and
operate the HVAC system. If the noise goes away,
possible causes include:
²Foreign material in the HVAC housing
²Improper blower motor mounting
²Improper blower wheel mounting
²Blower motor faulty.
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.
WJDISTRIBUTION 24 - 37