Electronic JEEP GRAND CHEROKEE 2003 WJ / 2.G Workshop Manual

STATOR
The stator assembly (Fig. 112) is mounted on a sta-
tionary shaft which is an integral part of the oil
pump. The stator is located between the impeller and
turbine within the torque converter case (Fig. 113).
The stator contains an over-running clutch, which
allows the stator to rotate only in a clockwise direc-
tion. When the stator is locked against the over-run-
ning clutch, the torque multiplication feature of the
torque converter is operational.
TORQUE CONVERTER CLUTCH (TCC)
The TCC (Fig. 114) was installed to improve the
efficiency of the torque converter that is lost to the
slippage of the fluid coupling. Although the fluid cou-
pling provides smooth, shock-free power transfer, it is
natural for all fluid couplings to slip. If the impeller
and turbine were mechanically locked together, a
zero slippage condition could be obtained. A hydraulic
piston with friction material was added to the tur-
bine assembly to provide this mechanical lock-up.
In order to reduce heat build-up in the transmission
and buffer the powertrain against torsional vibrations,
the TCM can duty cycle the L/R-CC Solenoid to achieve
a smooth application of the torque converter clutch.
This function, referred to as Electronically Modulated
Converter Clutch (EMCC) can occur at various times
depending on the following variables:
²Shift lever position
²Current gear range
²Transmission fluid temperature
²Engine coolant temperature
²Input speed
²Throttle angle
²Engine speed
Fig. 112 Stator Components
1 - CAM (OUTER RACE)
2 - ROLLER
3 - SPRING
4 - INNER RACE
Fig. 113 Stator Location
1-STATOR
2 - IMPELLER
3 - FLUID FLOW
4 - TURBINE
Fig. 114 Torque Converter Clutch (TCC)
1 - IMPELLER FRONT COVER
2 - THRUST WASHER ASSEMBLY
3 - IMPELLER
4-STATOR
5 - TURBINE
6 - PISTON
7 - FRICTION DISC
WJAUTOMATIC TRANSMISSION - 545RFE 21 - 267
TORQUE CONVERTER (Continued)

POSITION SENSOR
DESCRIPTION
The transfer case position sensor (Fig. 95) is an
electronic device whose output can be interpreted to
indicate the transfer case's current operating mode.
The sensor consists of a five position, resistive multi-
plexed circuit which returns a specific resistance
value to the Powertrain Control Module (PCM) for
each transfer case operating mode. The sensor is
located on the top of the transfer case, just left of the
transfer case centerline and rides against the sector
plate roostercomb. The PCM supplies 5VDC (+/-
0.5V) to the sensor and monitors the return voltage
to determine the sector plate, and therefore the
transfer case, position.
OPERATION
During normal vehicle operation, the Powertrain
Control Module (PCM) monitors the transfer case
position sensor return voltage to determine the oper-
ating mode of the transfer case. Refer to the Operat-
ing Mode Versus Resistance table for the correct
resistance for each position (Fig. 96).
OPERATING MODE VERSUS RESISTANCE
SENSOR POSITION OPERATING MODE SENSOR RESISTANCE (ohms)
1 2WD 1124-1243
2 4WD PART TIME 650-719
3 4WD FULL TIME 389-431
4 NEUTRAL 199-221
5 4WD LOW 57-64
Fig. 96 Position Sensor Linear Movement
1 - POSITION 1 - 10mm  0.5mm
2 - POSITION 2 - 12mm  0.5mm
3 - POSITION 3 - 14mm  0.5mm
4 - POSITION 4 - 16mm  0.5mm
5 - POSITION 5 - 18mm  0.5mm
6 - POSITION 6 - 20mm 0.5mm - FULL EXTENSION
Fig. 95 Transfer Case Position Sensor and
Connector
1 - TRANSFER CASE POSITION SENSOR CONNECTOR
2 - TRANSFER CASE POSITION SENSOR
3 - TRANSFER CASE
4 - OUTPUT SPEED SENSOR CONNECTOR
WJTRANSFER CASE - NV242 21 - 311

TIRE PRESSURE MONITORING
DESCRIPTION
The EVIC will monitor the tire pressure signals
from the five tire sensors and determine if any tire
has gone below the low pressure threshold or raised
above the high pressure threshold. Refer to the table
below.
LOW TIRE PRESSURE THRESHOLDS
SYSTEM STATUS
INDICATORTIRE PRESSURE
ON 179 kPa (26 PSI)
OFF 214 kPa (31 PSI)
HIGH TIRE PRESSURE THRESHOLDS
SYSTEM STATUS
INDICATORTIRE PRESSURE
ON 310 kPa (45 PSI)
OFF 276 kPa (40 PSI)
The Remote Tire Pressure Monitors (RTPM) are
not internally serviceable. For a Sensor Failure or
Low Battery fault, the RTPM must be replaced.
OPERATION
If equipped with the Tire Pressure Monitoring Sys-
tem, each of the vehicle's five wheels will have a
valve stem with a pressure sensor and radio trans-
mitter built in. Signals from the tire pressure sensors
are received and interpreted by the Electronic Vehi-
cle Information Center (EVIC). A sensor in a
mounted wheel will broadcast its detected pressure
once per minute when the vehicle is moving faster
than 40 km/h (25 mph). The spare tire sensor will
broadcast once every hour. Each sensor's broadcast is
uniquely coded so that the EVIC can determine loca-
tion. The individual tire pressures can be displayed
graphically on the EVIC
DIAGNOSIS AND TESTING - TIRE PRESSURE
MONITORING SYSTEM
All Tire Pressure Monitoring System Faults are
specific to one location. If a9BATTERY LOW9or
9SENSOR FAILURE9fault is detected, the location
will be displayed. The appropriate sensor/transmitter
can then be replaced. If a single sensor/transmitter
cannot be detected by the EVIC, replace that sensor
transmitter. If none of the sensors/transmitters can
be detected, refer to symptoms in the EVIC section.
For additional system description and diagnosis,
refer to Tire Pressure Monitoring in the Body Diag-
nostic manual.
SENSOR
REMOVAL - TIRE PRESSURE SENSOR/
TRANSMITTER
(1) Remove the tire/wheel from the vehicle.
CAUTION: When removing the stick on balancing
weights from the wheel, do not use an abrasive
cleaner or a cleaner which will damage the protec-
tive finish on the wheel.
(2) Remove the balancing weights from the wheel.
NOTE: The cap used on this valve stem contains an
O-ring seal to prevent contamination and moisture
from entering the valve stem. Retain this valve stem
cap for re-use. Do not substitute a regular valve
stem cap in its place.
(3) Remove the cap from the valve stem.
NOTE: The valve stem used on this vehicle is made
of aluminum and the core is nickel plated brass.
The original valve stem core must be reinstalled
and not substituted for a valve stem core made of a
different material. This is required to prevent corro-
sion in the valve stem caused by the different met-
als.
(4) Using the appropriate tool, remove the core
from the valve stem (Fig. 20).
(5) Let the tire fully deflate.
Fig. 20 REMOVING VALVE STEM CORE - TYPICAL
1 - WHEEL
2 - VALVE STEM
3 - TIRE
4 - VALVE STEM CORE TOOL
22 - 12 TIRES/WHEELSWJ

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

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)

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

(2)If there are no fault codes, the ª00º dis-
play value will remain in the VF window.Should
there be any codes, each will be displayed for one
second in ascending numerical sequence (note: no
effort is made to display faults in the order they
occurred). The left side set temperature display will
be blanked and the right side set temperature dis-
play will indicate current and historical codes (8 his-
torical max) presently active. Once all codes have
been displayed, the system will repeat the fault code
numbers. This will continue until the left side set
temperature control is moved at least one detent
position in either direction, by pressing both the A/C
and Recirc buttons at the same time, or the ignition
is turned off. Record all of the fault codes, then see
the Current and Historical Fault Code charts for the
descriptions.
CLEARING FAULT CODES
Current faults cannot be electronically cleared.
Repair must be made to the system to eliminate the
fault causing code. Historical fault codes can be
cleared manually, or automatically. To clear a histor-
ical fault manually, depress and hold either the A/C
or Recirc button for at least three seconds while the
display is in the fault code mode of operation. Histor-
ical fault codes are cleared automatically when the
corresponding current fault code has been cleared,
and has remained cleared for a number of ignition
cycles. The faults have been cleared when two hori-
zontal bars appear in the Test Selector display.
EXITING SELF-DIAGNOSTIC MODE
The self-diagnostic mode can be exited by pressing
both the A/C and Recirc buttons at the same time, or
turning off the ignition.
MONITOR CURRENT PARAMETERS
While in the display fault code mode of operation,
current system parameters can also be monitored
and/or forced. Rotating the left side set temperature
control clockwise will increase the pointer number
while rotating the control counter clockwise will
decrease the pointer number. Rotating the right set
temperature control will have no impact on pointer
value or the value of the parameter being monitored.
Once the desired pointer number has been selected,
pressing either the AC or Recirc buttons will display
the current value of the selected parameter.The
right side set temperature display is only capa-
ble of displaying only values ranging from 0 to
99, the left side set temperature display is used
for values greater than 99. If the value is less
than 99, the left side set temperature display
remains blanked.While a parameter is being over-
ridden, the system will continue to function normallyexcept for the parameter which is being manually
controlled.
For values < 0, the9G9segment in the left side set
temperature Most Significant Digit (MSD)(or left-
most number in the pair) will be used to indicate a
negative number. For values between -01 to -99 the
Least Significant Digit (LSD)(or right-most number
of the pair) in the left side set temperature will
remain blank. System control of parameter being dis-
played can be overridden by rotating the right set
temperature control in either direction. Rotating the
right temperature control in the CW direction, the
selected parameter value is overridden and incre-
mented beginning at the value which was being dis-
played. Rotating the right temperature control in the
CCW direction, the selected parameter value is over-
ridden and decremented beginning at the value
which was being displayed. The rate at which incre-
menting and decrement occurs is one unit value per
set temperature detent position.
HVAC SYSTEM POINTER
Pointer
NumberDESCRIPTION Value
Displayed
01 A/C Enable 0 or 1
0=
disabled
1=
enabled
02 Final fan PWM duty cycle 0 to 255
While the value of this pointer
is being displayed, turning the
right set temperature control
either direction will manually
control the value. CW =
increase; CCW = decrease
03 Left NPRG * 0 to 255
* NPRG equals a calculated number based on outside
and in-vehicle conditions. This value is used by the
AZC to position the Mode motor, Air Inlet motor, and
control blower motor speed.
While the value of this pointer
is being displayed, turning the
right set temperature control
either direction will manually
control the value. CW =
increase; CCW = decrease
04 Right NPRG 0 to 255
WJCONTROLS 24 - 21
A/C HEATER CONTROL (Continued)

HVAC HOUSING
REMOVAL
The HVAC housing assembly must be removed
from the vehicle and the two halves of the housing
separated for service access of the heater core, evap-
orator coil, blend door(s), and each of the various
mode doors.
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.
WARNING: REVIEW THE WARNINGS AND CAU-
TIONS IN PLUMBING BEFORE PERFORMING THE
FOLLOWING OPERATION. (Refer to 24 - HEATING &
AIR CONDITIONING/PLUMBING - WARNING) (Refer
to 24 - HEATING & AIR CONDITIONING/PLUMBING -
CAUTION)
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the instrument panel from the vehi-
cle(Refer to 23 - BODY/INSTRUMENT PANEL -
REMOVAL).
(3) Recover the refrigerant from the refrigerant
system. (Refer to 24 - HEATING & AIR CONDI-
TIONING/PLUMBING - STANDARD PROCEDURE -
REFRIGERANT RECOVERY)
(4) Disconnect the liquid line refrigerant line from
the evaporator inlet tube(Refer to 24 - HEATING &
AIR CONDITIONING/PLUMBING/LIQUID LINE -
REMOVAL) or (Refer to 24 - HEATING & AIR CON-
DITIONING/PLUMBING/LIQUID LINE - REMOV-
AL). Install plugs in, or tape over all of the opened
refrigerant line fittings.
(5) Disconnect the suction line refrigerant line
from the evaporator outlet tube(Refer to 24 - HEAT-
ING & AIR CONDITIONING/PLUMBING/SUCTION
LINE - REMOVAL), (Refer to 24 - HEATING & AIR
CONDITIONING/PLUMBING/SUCTION LINE -
REMOVAL) or (Refer to 24 - HEATING & AIR CON-
DITIONING/PLUMBING/SUCTION LINE - REMOV-
AL). Install plugs in, or tape over all of the opened
refrigerant line fittings.(6) Disconnect the heater hoses from the heater
core tubes. Clamp off the heater hoses to prevent loss
of coolant. Refer to Cooling for the procedures. Install
plugs in, or tape over the opened heater core tubes.
(7) If the vehicle is equipped with the manual tem-
perature control system, unplug the HVAC system
vacuum supply line connector from the tee fitting
near the heater core tubes.
(8) Remove the coolant reserve/overflow bottle
from the passenger side inner fender shield. Refer to
Cooling for the procedures.
(9) Remove the Powertrain Control Module (PCM)
from the passenger side dash panel in the engine
compartment and set it aside. Do not unplug the
PCM wire harness connectors. Refer to Electronic
Control Modules for the procedures.
(10) Remove the nuts from the HVAC housing
mounting studs on the engine compartment side of
the dash panel (Fig. 9).
(11) Remove the rear floor heat ducts from the
floor heat duct outlets (Fig. 10).
(12) Unplug the HVAC housing wire harness con-
nectors.
(13) Remove the HVAC housing mounting nuts
from the studs on the passenger compartment side of
the dash panel (Fig. 11).
Fig. 9 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
WJDISTRIBUTION 24 - 41

NOTE: The blend door sub-assembly is attached to
the housing with 2 screws, and may be removed for
service (Fig. 19).
ASSEMBLY
(1) Place the top half of the HVAC housing on the
bottom half. Be certain that each of the door pivot
pins align with the pivot holes in the HVAC housing.
(2) Install the 10 screws that secure the two hous-
ing halves to each other. Tighten the HVAC housing
screws to 2.2 N´m (20 in. lbs.).
(3) Attach the wire harness electrical connector(s)
to the mounts on the lower case at the blower motor
end of the unit.
(4) Install the 5 clips that secure the two housing
halves to each other. Check doors for binding after
replacement, and after assembly of housing.
(5) Install the screw with plastic washer holding
the lever assembly to the upper case section.
(6) Install the mode door actuator on the left side
of the housing.
INSTALLATION
WARNING: REVIEW THE WARNINGS AND CAU-
TIONS IN PLUMBING BEFORE PERFORMING THE
FOLLOWING OPERATION. (Refer to 24 - HEATING &
AIR CONDITIONING/PLUMBING - WARNING) (Refer
to 24 - HEATING & AIR CONDITIONING/PLUMBING -
CAUTION)Any kinks or sharp bends in the refrigerant plumb-
ing will reduce the capacity of the entire air condi-
tioning system. Kinks and sharp bends reduce the
flow of refrigerant in the system. A good rule for the
flexible hose refrigerant lines is to keep the radius of
all bends at least ten times the diameter of the hose.
In addition, the flexible hose refrigerant lines should
be routed so they are at least 80 millimeters (3
inches) from the exhaust manifold.
High pressures are produced in the refrigerant sys-
tem when the air conditioning compressor is operat-
ing. Extreme care must be exercised to make sure
that each of the refrigerant system connections is
pressure-tight and leak free. It is a good practice to
inspect all flexible hose refrigerant lines at least once
a year to make sure they are in good condition and
properly routed.
(1) Position the HVAC housing to the dash panel.
Be certain that the evaporator condensate drain tube
and the housing mounting studs are inserted into
their correct mounting holes.
(2) Install the HVAC housing mounting nuts to the
studs on the passenger compartment side of the dash
panel. Tighten the nuts to 4.5 N´m (40 in. lbs.).
(3) Connect the HVAC housing wire harness con-
nectors.
(4) Reinstall the rear floor heat ducts to the center
floor heat duct outlets.
(5) Install and tighten the nuts onto the HVAC
housing mounting studs on the engine compartment
side of the dash panel. Tighten the nuts to 7 N´m (60
in. lbs.).
(6) Reinstall the PCM to the passenger side dash
panel in the engine compartment. Refer to Electronic
Control Modules for the procedures.
(7) Reinstall the coolant reserve/overflow bottle to
the passenger side inner fender shield. Refer to Cool-
ing for the procedures.
(8) If the vehicle is equipped with the manual tem-
perature control system, connect the HVAC system
vacuum supply line connector to the tee fitting near
the heater core tubes.
(9) Unclamp/unplug the heater core hoses and
tubes. Connect the heater hoses to the heater core
tubes and fill the engine cooling system. Refer to
Cooling for the procedures.
(10) Unplug or remove the tape from the suction
line and the evaporator outlet tube fittings. Connect
the suction line to the evaporator outlet tube.
Tighten retaining nut to 28 N´m (250 in. lbs.).
(11) Unplug or remove the tape from the liquid
line and the evaporator inlet tube fittings. Connect
the liquid line to the evaporator inlet tube. Tighten
retaining nut to 28 N´m (250 in. lbs.).
(12) Evacuate the refrigerant system. (Refer to 24
- HEATING & AIR CONDITIONING/PLUMBING -
Fig. 19 BLEND DOOR SUB-ASSEMBLY (AZC)
1 - PASSENGER SIDE BLEND DOOR
2 - BLEND DOOR SUB-ASSEMBLY
3 - DOOR PIVOT SHAFT BUSHING
4 - DOOR SHAFT LEVER
5 - DRIVER SIDE BLEND DOOR
WJDISTRIBUTION 24 - 45
HVAC HOUSING (Continued)

VISCOUS HEATER
DESCRIPTION
DESCRIPTION........................76
DESCRIPTION - VISCOUS HEATER
CLUTCH............................76
OPERATION
OPERATION - VISCOUS HEATER.........76
OPERATION - VISCOUS HEATER CLUTCH . . 76REMOVAL
REMOVAL - VISCOUS HEATER...........76
REMOVAL - VISCOUS HEATER CLUTCH . . . 76
INSTALLATION
INSTALLATION.......................78
INSTALLATION - VISCOUS HEATER
CLUTCH............................78
PLUMBING
DESCRIPTION - REFRIGERANT LINE
The refrigerant lines and hoses are used to carry
the refrigerant between the various air conditioning
system components. A barrier hose design with a
nylon tube, which is sandwiched between rubber lay-
ers, is used for the R-134a air conditioning system on
this vehicle. This nylon tube helps to further contain
the R-134a refrigerant, which has a smaller molecu-
lar structure than R-12 refrigerant. The ends of the
refrigerant hoses are made from lightweight alumi-
num or steel, and commonly use braze-less fittings.
Any kinks or sharp bends in the refrigerant plumb-
ing will reduce the capacity of the entire air condi-
tioning system. Kinks and sharp bends reduce the
flow of refrigerant in the system. A good rule for the
flexible hose refrigerant lines is to keep the radius of
all bends at least ten times the diameter of the hose.
In addition, the flexible hose refrigerant lines should
be routed so they are at least 80 millimeters (3
inches) from the exhaust manifold.
OPERATION - REFRIGERANT LINE
High pressures are produced in the refrigerant sys-
tem when the air conditioning compressor is operat-
ing. Extreme care must be exercised to make sure
that each of the refrigerant system connections is
pressure-tight and leak free. It is a good practice to
inspect all flexible hose refrigerant lines at least once
a year to make sure they are in good condition and
properly routed.
The refrigerant lines and hoses cannot be repaired
and, if faulty or damaged, they must be replaced.
WARNING
WARNING: THE AIR CONDITIONING SYSTEM CON-
TAINS REFRIGERANT UNDER HIGH PRESSURE.
SEVERE PERSONAL INJURY MAY RESULT FROM
IMPROPER SERVICE PROCEDURES. REPAIRS
SHOULD ONLY BE PERFORMED BY QUALIFIED
SERVICE PERSONNEL.
AVOID BREATHING THE REFRIGERANT AND
REFRIGERANT OIL VAPOR OR MIST. EXPOSURE
MAY IRRITATE THE EYES, NOSE, AND/OR THROAT.
WEAR EYE PROTECTION WHEN SERVICING THE
AIR CONDITIONING REFRIGERANT SYSTEM. SERI-
OUS EYE INJURY CAN RESULT FROM DIRECT
CONTACT WITH THE REFRIGERANT. IF EYE CON-
TACT OCCURS, SEEK MEDICAL ATTENTION IMME-
DIATELY.
DO NOT EXPOSE THE REFRIGERANT TO OPEN
FLAME. POISONOUS GAS IS CREATED WHEN
REFRIGERANT IS BURNED. AN ELECTRONIC LEAK
DETECTOR IS RECOMMENDED.
IF ACCIDENTAL SYSTEM DISCHARGE OCCURS,
VENTILATE THE WORK AREA BEFORE RESUMING
SERVICE. LARGE AMOUNTS OF REFRIGERANT
RELEASED IN A CLOSED WORK AREA WILL DIS-
PLACE THE OXYGEN AND CAUSE SUFFOCATION.
THE EVAPORATION RATE OF R-134a REFRIGER-
ANT AT AVERAGE TEMPERATURE AND ALTITUDE
IS EXTREMELY HIGH. AS A RESULT, ANYTHING
THAT COMES IN CONTACT WITH THE REFRIGER-
ANT WILL FREEZE. ALWAYS PROTECT THE SKIN
OR DELICATE OBJECTS FROM DIRECT CONTACT
WITH THE REFRIGERANT.
THE R-134a SERVICE EQUIPMENT OR THE VEHI-
CLE REFRIGERANT SYSTEM SHOULD NOT BE
PRESSURE TESTED OR LEAK TESTED WITH COM-
PRESSED AIR. SOME MIXTURES OF AIR AND
R-134a HAVE BEEN SHOWN TO BE COMBUSTIBLE
AT ELEVATED PRESSURES. THESE MIXTURES ARE
POTENTIALLY DANGEROUS, AND MAY RESULT IN
FIRE OR EXPLOSION CAUSING INJURY OR PROP-
ERTY DAMAGE.
24 - 52 PLUMBINGWJ