blower motor JEEP GRAND CHEROKEE 2002 WJ / 2.G User Guide

(35) Disconnect the two instrument panel wire
harness connectors from the two heater and air con-
ditioner housing connectors located near the blower
motor on the passenger side end of the housing (Fig.
12).
(36) Remove the two screws that secure the pas-
senger side instrument panel structural duct to the
heater and air conditioner housing (Fig. 13).(37) Remove the two screws that secure the instru-
ment panel to the passenger side cowl side inner
panel (Fig. 14).
(38) With the aid of an assistant, lift the instru-
ment panel assembly upward off of the studs on the
dash panel near the windshield fence line and to dis-
engage the molded plastic hook formations on the
instrument panel structural duct from the guide
holes at each cowl side inner panel.
(39)
Pull the instrument panel rearward from the
dash panel and the cowl side inner panels and remove it
through the driver side front door of the vehicle.
Fig. 12 Heater and Air Conditioner Housing
Connections
1 - INSTRUMENT PANEL
2 - HVAC HOUSING
3 - INSTRUMENT PANEL WIRE HARNESS
4 - BLOWER MOTOR
Fig. 13 Passenger Side Instrument Panel to
Heater-A/C Housing Mounting
1 - HEATER AND AIR CONDITIONER HOUSING
2 - INSTRUMENT PANEL STRUCTURAL DUCT
3 - SCREW (2)
Fig. 14 Instrument Panel to Passenger Side Cowl
Side Inner Panel Mounting
1 - COWL SIDE INNER PANEL
2 - INSTRUMENT PANEL STRUCTURAL DUCT
3 - SCREW (2)
23 - 42 INSTRUMENT PANEL SYSTEMWJ
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)

releasing the control switch before the sunroof was
fully closed. The sunroof module has a water-man-
agement system. During washing high-pressure
water may be forced between the glass panel seal
and the roof opening. Normally this water will drain.
However, when some type of drying blower system is
used, like those found in automatic car washes, thewater may not have a chance to drain before the
blower forces air between the seal and the roof open-
ing. This causes the water to blow over the edge of
the module and onto the headlining.
Refer to (Fig. 1) Sunroof Assembly for exploded
view of the sunroof.
SYMPTOM STEP POSSIBLE CAUSE
Sunroof squeaks when
opening/closing.1 Identify if the cause is a seal squeak. If seal is worn, replace the
seal.
2 Check seal compression for uniformity in opening, If not uniform,
glass is not centered in opening.
3 Re-center glass by repositioning module in opening.
4 Identify if mechanism squeaks.
5 Check for lubrication, re-lube if necessary.
6 Check for dirt/debris in tracks, clean and re-lube.
7 Identify if motor squeaks, replace the motor.
Water leaks into the vehicle. 1 Check for a good connection at the drain tubes, re-connect where
needed.
2 Check for plugged/pinched hoses throughout.
3 Adjust the glass panel. Refer to glass panel adjustments in this
section.
4 Check seal for wear/damage, replace glass as necessary.
Motor inoperative. 1 Check connectors at the motor, switch, control module and power
source.
2 Check for defective control module, replace if necessary.
3 Replace the motor.
Motor noise when opening/
closing.1 Identify if motor noise, replace motor.
2 Insure noise is from the motor and not cables, (cable ratcheting).
Grinding noise when opening/
closing.1 Identify if the motor is grinding, replace motor.
(Mechanism noise, scraping.) 2 Check for lubrication in tracks and mechanism, re-lube if
necessary.
3 Check for dirt/debris in tracks, clean and re-lube.
(Cable ratcheting.) 4 Cables ratchet at the motor pinion; mechanism jammed, fix
mechanism and replace cables and motor bracket.
Wind noise when sunroof fully
closed.1 Check seal compression for uniformity in opening, If not uniform,
glass is not centered in opening.
2 Glass not adjusted flush to roof. Refer to glass panel adjustments
in this section.
3 Mechanism not fully closed.
A) Motor out of time, re-time motor/mechanism. Refer to glass
panel adjustments in this section.
B) Cable ratcheting, replace cables and motor bracket.
4 Seal worn, replace glass.
Sunroof will not open/close. 1 Check switch and switch connection.
WJSUNROOF 23 - 97
SUNROOF (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)

However, evaporator capacity used to reduce the
amount of moisture in the air is not wasted. Wring-
ing some of the moisture out of the air entering the
vehicle adds to the comfort of the passengers.
Although, an owner may expect too much from their
air conditioning system on humid days. A perfor-
mance test is the best way to determine whether the
system is performing up to standard. This test also
provides valuable clues as to the possible cause of
trouble with the air conditioning system.
If the vehicle has the optional Automatic Zone Control
(AZC) system, and has intermittent operational prob-
lems or fault codes, be certain that the wire harness
connectors on the HVAC housing are properly seated
(Fig. 2). To check this condition, unplug the two wire
harness connector halves, then plug them in again.
Before performing the following procedure, (Refer
to 24 - HEATING & AIR CONDITIONING/PLUMB-
ING - CAUTION) (Refer to 24 - HEATING & AIR
CONDITIONING/PLUMBING - WARNING). The air
temperature in the test room and in the vehicle must
be a minimum of 21É C (70É F) for this test.
(1)
Connect a tachometer and a manifold gauge set.
(2) If the vehicle has the standard manual temper-
ature control, set the A/C Heater mode control switch
knob in the Panel position, the temperature control
knob in the full cool (Fresh Air Mode) position, the
A/C button in the On position, and the blower motor
switch knob in the highest speed position. If the vehi-
cle has the optional AZC, set the A/C Heater mode
control switch knob in the Panel position, the tem-
perature control knob in the full cool position, the
A/C button in the On position, and the blower motor
switch knob in the highest (manual) speed position.
(3) Start the engine and hold the idle at 1,300 rpm
with the compressor clutch engaged.
(4) The engine should be at operating temperature.
The doors and windows must be open.
(5)
Insert a thermometer in the driver side center
A/C (panel) outlet. Operate the engine for five minutes.
(6) The compressor clutch may cycle, depending
upon the ambient temperature and humidity.(7) With the compressor clutch engaged, record the
discharge air temperature and the compressor dis-
charge pressure.
(8) Compare the discharge air temperature to the
Performance Temperature and Pressure chart. If the
discharge air temperature is high, (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
DIAGNOSIS AND TESTING - REFRIGERANT SYS-
TEM LEAKS) and (Refer to 24 - HEATING & AIR
CONDITIONING/PLUMBING - STANDARD PRO-
CEDURE - REFRIGERANT SYSTEM CHARGE).
Performance Temperature and Pressure
Ambient Air Temperature
and Humidity21É C
(70É F @ 80%
humidity)27É C
(80É F @ 80%
humidity)32É C
(90É F @ 80%
humidity)38É C
(100ÉF@50%
humidity)43É C
110É F @ 20%
humidity)
Air Temperature at Center
Panel Outlet10 to 13É C
(50 to 55É F)14 to 17É C
(58 to 63É F)15 to 18É C
(60 to 65É F)17 to 20É C
(63 to 68É F)14 to 17É C
(58 to 63É F)
Evaporator Inlet Pressure
at Charge Port241 to 276 kPa
(35 to 40 psi)262 to 290 kPa
(38 to 42 psi)269 to 296 kPa
(39 to 43 psi)275 to 303 kPa
(40 to 44 psi)262 to 290 kPa
(38 to 42 psi)
Compressor Discharge
Pressure1241 to 1792
kPa
(180 to 260 psi)1380 to 1930
kPa
(200 to 280 psi)1380 to 1930
kPa
(200 to 280 psi)1655 to 2206
kPa
(240 to 320 psi)1567 to 2068
kPa
(220 to 300 psi)
Note: The discharge air temperatures will be lower if the humidity is less than the percentages shown.
Fig. 2 HVAC Housing - (rear view)
1 - Instrument Panel
2 - Air Intake
3 - Expansion Valve
4 - HVAC Housing
5 - Heater Core Input/Output Ports
6 - Instrument Panel Wiring Harness
7 - Blower Motor
WJHEATING & AIR CONDITIONING 24 - 3
HEATING & AIR CONDITIONING (Continued)

DIAGNOSIS AND TESTING - HEATER
PERFORMANCE
Before performing the following tests, refer to Cool-
ing for the procedures to check the radiator coolant
level, serpentine drive belt tension, radiator air flow
and the radiator fan operation. Also be certain that
the accessory vacuum supply line is connected at the
engine intake manifold for the manual temperature
control system.
MAXIMUM HEATER OUTPUT
Engine coolant is delivered to the heater core
through two heater hoses. With the engine idling at
normal operating temperature, set the temperature
control knob in the full hot position, the mode control
switch knob in the floor heat position, and the blower
motor switch knob in the highest speed position.
Using a test thermometer, check the temperature of
the air being discharged at the HVAC housing floor
outlets. Compare the test thermometer reading to the
Temperature Reference chart.
Temperature Reference
Ambient Air Temperature15.5É C
(60É F)21.1É C
(70É F)26.6É C
(80É F)32.2É C
(90É F)
Minimum Air Temperature at
Floor Outlet62.2É C
(144É F)63.8É C
(147É F)65.5É C
(150É F)67.2É C
(153É F)
If the floor outlet air temperature is too low, refer
to Cooling to check the engine coolant temperature
specifications. Both of the heater hoses should be hot
to the touch. The coolant return heater hose should
be slightly cooler than the coolant supply heater
hose. If the return hose is much cooler than the sup-
ply hose, locate and repair the engine coolant flow
obstruction in the cooling system. Refer to Cooling
for the procedures.
OBSTRUCTED COOLANT FLOW
Possible locations or causes of obstructed coolant
flow:
²Pinched or kinked heater hoses.
²Improper heater hose routing.
²Plugged heater hoses or supply and return ports
at the cooling system connections.
²A plugged heater core.
If proper coolant flow through the cooling system is
verified, and heater outlet air temperature is still
low, a mechanical problem may exist.
MECHANICAL PROBLEMS
Possible locations or causes of insufficient heat:
²An obstructed cowl air intake.
²Obstructed heater system outlets.
²A blend door not functioning properly.
TEMPERATURE CONTROL
If the heater outlet air temperature cannot be
adjusted with the temperature control knob(s) on the
A/C Heater control panel, the following could require
service:
²The A/C heater control.
²The blend door actuator(s).
²The wire harness circuits for the A/C heater con-
trol or the blend door actuator(s).²The blend door(s).
²Improper engine coolant temperature.
STANDARD PROCEDURE - DIODE
REPLACEMENT
(1) Disconnect and isolate the negative battery
cable.
(2) Locate the diode in the harness, and remove
the protective covering.
(3) Remove the diode from the harness, pay atten-
tion to the current flow direction (Fig. 3).
(4) Remove the insulation from the wires in the
harness. Only remove enough insulation to solder in
the new diode.
Fig. 3 DIODE IDENTIFICATION
1 - CURRENT FLOW
2 - BAND AROUND DIODE INDICATES CURRENT FLOW
3 - DIODE AS SHOWN IN THE DIAGRAMS
24 - 6 HEATING & AIR CONDITIONINGWJ
HEATING & AIR CONDITIONING (Continued)

(5) Install the new diode in the harness, making
sure current flow is correct. If necessary refer to the
appropriate wiring diagram for current flow.
(6) Solder the connection together using rosin core
type solder only.Do not use acid core solder.
(7) Tape the diode to the harness using electrical
tape making, sure the diode is completely sealed
from the elements.
(8) Re-connect the battery, and test affected sys-
tems.SPECIFICATIONS
A/C APPLICATION TABLE
Item Description Notes
VEHICLE WJ - Grand
Cherokee
SYSTEM R134a w/
expansion valve
COMPRESSOR Nippondenso
10PA17ND-8 PAG oil
Freeze±up
ControlEvaporator Probe Evaporator
mounted
Low psi Control opens < 22 psi -
resets > 34-38 psi
High psi Control opens > 450-490
psi - resets <
270-330 psiline mounted
CONTROL
HEADManual type manual
controls
Automatic Zone
Control (AZC)Automatic
Zone Control
(AZC) with
dual infrared
sensing
Mode Doors Vacuum actuators
(manual)electric
actuator
(AZC)
Blend Door Electric actuator (manual and
AZC)
Blend Door
(passenger)Electric actuator (AZC only)
Recirculation
DoorVacuum actuator
(manual)electric
actuator
(AZC)
Blower Motor Hardwired to
control head
resistor block
(manual),
blower
controller (AZC)
COOLING FAN Hybrid - viscous
clutch/electricPCM output
CLUTCH
Control Relay PCM
controlled
Draw
2.0-3.9 amps @ 12 V  0.5V@ 70É F
Gap 0.0169-0.0319
DRB IIIT
Reads TPS, RPM, A/C
switch
Actuators Clutch relay
WJHEATING & AIR CONDITIONING 24 - 7
HEATING & AIR CONDITIONING (Continued)

TORQUE SPECIFICATIONS
TORQUE SPECIFICATIONS
DESCRIPTION N´m Ft. Lbs. In. Lbs.
A/C COMPRESSOR
SHAFT BOLT13 9.6 115
A/C COMPRESOR LINE
MANIFOLD FASTENERS
4.0L/4.7L25.4 18.75 225
A/C COMPRESOR LINE
MANIFOLD FASTENERS
2.7L DIESEL22 16.2 195
A/C COMPRESSOR TO
ENGINE BLOCK BOLTS -
4.0L/4.7L45-65 33-48 398-575
A/C COMPRESSOR TO
ENGINE BLOCK BOLTS -
2.7L DIESEL30 22 266
A/C COMPRESSOR REAR
BRACE BOLTS - 4.0L40-55 30-41 354-487
A/C COMPRESSOR REAR
BRACE BOLTS - 4.7L35-45 26-33 310-398
A/C CONDENSER TO
REFRIG. LINE
FASTENERS28 21 248
A/C EVAPORATOR LINE to
TXV FASTENERS28 21 247
ACCUMULATOR
RETAINING BAND
(4.0L/4.7L)12 9.0 106
ACCUMULATOR
RETAINING BAND (3.1L
DIESEL)5 3.7 44
BLOWER MOTOR
SCREWS2.2 1.7 20
DOOR ACTUATOR
SCREWS2.2 1.7 20
HVAC HOUSING SCREWS 2.2 1.7 20
HVAC HOUSING TO DASH
PANEL NUTS (ENGINE
COMP. SIDE)75 62
HVAC HOUSING TO DASH
PANEL NUTS
(PASSENGER COMP.
SIDE)4.5 3.3 40
EXPANSION VALVE TO
HVAC FASTENERS20 15 177
SUCTION LINE TO
ACCUMULATOR FITTING28 20.7 248
24 - 8 HEATING & AIR CONDITIONINGWJ
HEATING & AIR CONDITIONING (Continued)

CONTROLS
TABLE OF CONTENTS
page page
CONTROLS
DIAGNOSIS AND TESTING - VACUUM
SYSTEM............................10
A/C COMPRESSOR CLUTCH
DESCRIPTION.........................13
OPERATION...........................13
DIAGNOSIS AND TESTING - COMPRESSOR
CLUTCH COIL........................13
STANDARD PROCEDURE - COMPRESSOR
CLUTCH BREAK-IN....................14
REMOVAL.............................14
INSPECTION..........................15
INSTALLATION.........................15
A/C COMPRESSOR CLUTCH RELAY
DESCRIPTION.........................16
OPERATION...........................16
DIAGNOSIS AND TESTING - A/C
COMPRESSOR CLUTCH RELAY..........16
REMOVAL.............................17
INSTALLATION.........................17
A/C HEATER CONTROL
DESCRIPTION.........................17
OPERATION...........................17
DIAGNOSIS AND TESTING - AUTOMATIC
ZONE CONTROL SYSTEM..............18
REMOVAL.............................24
INSTALLATION.........................25
A/C PRESSURE TRANSDUCER
DESCRIPTION.........................25
OPERATION...........................25
DIAGNOSIS AND TESTING - A/C PRESSURE
TRANSDUCER.......................26
REMOVAL.............................26
INSTALLATION.........................26
BLOWER MOTOR CONTROLLER
DESCRIPTION.........................26
OPERATION...........................26
REMOVAL.............................27
INSTALLATION.........................27
BLOWER MOTOR RESISTOR BLOCK
DESCRIPTION.........................27
OPERATION...........................27
DIAGNOSIS AND TESTING - BLOWER
MOTOR RESISTOR BLOCK..............27
REMOVAL.............................28
INSTALLATION.........................28BLOWER MOTOR SWITCH
DESCRIPTION.........................28
OPERATION...........................28
DIAGNOSIS AND TESTING - BLOWER
MOTOR SWITCH-MANUAL TEMPERATURE
CONTROL SYSTEM....................28
REMOVAL.............................29
IN-CAR TEMPERATURE SENSOR
DESCRIPTION.........................29
OPERATION...........................29
REMOVAL.............................29
BLEND DOOR ACTUATOR
DESCRIPTION.........................30
REMOVAL.............................30
INSTALLATION.........................30
MODE DOOR ACTUATOR
DESCRIPTION.........................30
REMOVAL
REMOVAL - HEAT/DEFROST - PANEL/
DEFROST DOOR ELECTRIC ACTUATOR . . . 31
REMOVAL - HEAT/DEFROST DOOR
VACUUM ACTUATOR..................31
REMOVAL - PANEL/DEFROST DOOR
VACUUM ACTUATOR..................32
INSTALLATION
INSTALLATION - HEAT/DEFROST -
PANEL/DEFROST DOOR ELECTRIC
ACTUATOR..........................32
INSTALLATION - HEAT/DEFROST DOOR
VACUUM ACTUATOR..................33
INSTALLATION - PANEL/DEFROST DOOR
VACUUM ACTUATOR..................33
RECIRCULATION DOOR ACTUATOR
DESCRIPTION.........................33
REMOVAL
REMOVAL - RECIRCULATION DOOR
VACUUM ACTUATOR..................33
REMOVAL - RECIRCULATION DOOR
ELECTRIC ACTUATOR.................33
INSTALLATION
INSTALLATION - RECIRCULATION DOOR
VACUUM ACTUATOR..................34
INSTALLATION - RECIRCULATION DOOR
ELECTRIC ACTUATOR.................34
VACUUM CHECK VALVE
DESCRIPTION.........................34
OPERATION...........................34
REMOVAL.............................34
INSTALLATION.........................34
WJCONTROLS 24 - 9

A/C COMPRESSOR CLUTCH
DESCRIPTION
The compressor clutch assembly consists of a sta-
tionary electromagnetic coil, a hub bearing and pul-
ley assembly, and a clutch plate (Fig. 4). The
electromagnetic coil unit and the hub bearing and
pulley assembly are each retained on the nose of the
compressor front housing with snap rings. The clutch
plate is keyed to the compressor shaft and secured
with a bolt.
OPERATION
The compressor clutch components provide the
means to engage and disengage the compressor from
the engine serpentine accessory drive belt. When the
clutch coil is energized, it magnetically draws the
clutch into contact with the pulley and drives the
compressor shaft. When the coil is not energized, the
pulley freewheels on the clutch hub bearing, which is
part of the pulley. The compressor clutch and coil are
the only serviced parts on the compressor.
The compressor clutch engagement is controlled by
several components: the a/c switch on the a/c heater
control panel, the Automatic Zone Control (AZC) con-
trol module (if the vehicle is so equipped), the evap-
orator probe, the a/c high pressure transducer, the
a/c compressor clutch relay, the body control module
(BCM) and the Powertrain Control Module (PCM).
The PCM may delay compressor clutch engagement
for up to thirty seconds. Refer to Electronic Control
Modules for more information on the PCM controls.
DIAGNOSIS AND TESTING - COMPRESSOR
CLUTCH COIL
For circuit descriptions and diagrams, refer to the
appropriate wiring diagrams. The battery must be
fully-charged before performing the following tests.
Refer to Battery for more information.
(1) Connect an ammeter (0 to 10 ampere scale) in
series with the clutch coil terminal. Use a voltmeter
(0 to 20 volt scale) with clip-type leads for measuring
the voltage across the battery and the compressor
clutch coil.
(2) With the a/c heater mode control switch in any
a/c mode, the a/c heater control a/c switch in the ON
position, and the blower motor switch in the lowest
speed position, start the engine and run it at normal
idle.
(3) The compressor clutch coil voltage should read
within 0.2 volts of the battery voltage. If there is
voltage at the clutch coil, but the reading is not
within 0.2 volts of the battery voltage, test the clutch
coil feed circuit for excessive voltage drop and repair
as required. If there is no voltage reading at the
clutch coil, use a DRBIIItscan tool and the appro-
priate diagnostic information for testing of the com-
pressor clutch circuit. The following components
must be checked and repaired as required before you
can complete testing of the clutch coil:
²Fuses in the junction block and the Power Dis-
tribution Center (PDC)
²A/C heater mode control switch
²A/C compressor clutch relay
²A/C high pressure transducer
²A/C evaporator probe
²Powertrain Control Module (PCM)
²Body Control Module (BCM)
(4) The compressor clutch coil is acceptable if the
current draw measured at the clutch coil is 2.0 to 3.9
amperes with the electrical system voltage at 11.5 to
12.5 volts. This should only be checked with the work
area temperature at 21É C (70É F). If system voltage
is more than 12.5 volts, add electrical loads by turn-
ing on electrical accessories until the system voltage
drops below 12.5 volts.
(a) If the clutch coil current reading is four
amperes or more, the coil is shorted and should be
replaced.
(b) If the clutch coil current reading is zero, the
coil is open and should be replaced.
Fig. 4 COMPRESSOR CLUTCH - TYPICAL
1 - CLUTCH PLATE
2 - SHAFT KEY
3 - PULLEY
4 - COIL
5 - CLUTCH SHIMS
6 - SNAP RING
7 - SNAP RING
WJCONTROLS 24 - 13