
SHOULDER BELT HEIGHT ADJUSTER KNOB . . 64
SHOULDER BELT HEIGHT ADJUSTER±BOR
C-PILLAR............................ 64
SIDE VIEW MIRROR..................... 64
SLIDING DOOR CENTER HINGE............ 66
SLIDING DOOR CENTER STOP TRIM COVER . . 66
SLIDING DOOR CENTER STRIKER ASSEMBLY . 67
SLIDING DOOR HOLD OPEN LATCH STRIKER . 67
SLIDING DOOR HOLD OPEN LATCH......... 67
SLIDING DOOR INSIDE LATCH HANDLE
BELLCRANK.......................... 68
SLIDING DOOR INSIDE LATCH HANDLE...... 68
SLIDING DOOR INSIDE LATCH RELEASE
MECHANISM.......................... 69
SLIDING DOOR LATCH STRIKER........... 69
SLIDING DOOR LATCH/LOCK CONTROL..... 70
SLIDING DOOR LOWER ROLLER ARM
BRACKET............................ 71
SLIDING DOOR LOWER ROLLER ARM....... 71SLIDING DOOR OUTSIDE LATCH RELEASE
HANDLE............................. 72
SLIDING DOOR REAR LATCH.............. 73
SLIDING DOOR SILL PLATE............... 73
SLIDING DOOR STABILIZER SOCKET........ 74
SLIDING DOOR STABILIZER............... 73
SLIDING DOOR STOP BUMPER............ 74
SLIDING DOOR TRIM PANEL............... 74
SLIDING DOOR UPPER ROLLER............ 75
SLIDING DOOR WEATHER-STRIP........... 75
SLIDING DOOR......................... 64
STICK-ON BODY SIDE MOLDING........... 75
SUN VISOR SUPPORT................... 78
SUN VISOR............................ 76
UPPER B-PILLAR TRIM COVER............. 78
UPPER C-PILLAR TRIM................... 80
ADJUSTMENTS
SLIDING DOOR ADJUSTMENTS............ 80
DIAGNOSIS AND TESTING
WATER LEAKS
Water leaks can be caused by poor sealing,
improper body component alignment, body seam
porosity, missing plugs, or blocked drain holes. Cen-
trifugal and gravitational force can cause water to
drip from a location away from the actual leak point,
making leak detection difficult. All body sealing
points should be water tight in normal wet-driving
conditions. Water flowing downward from the front of
the vehicle should not enter the passenger or luggage
compartment. Moving sealing surfaces will not
always seal water tight under all conditions. At
times, side glass or door seals will allow water to
enter the passenger compartment during high pres-
sure washing or hard driving rain (severe) condi-
tions. Overcompensating on door or glass
adjustments to stop a water leak that occurs under
severe conditions can cause premature seal wear and
excessive closing or latching effort. After completing
a repair, water-test vehicle to verify leak has stopped
before returning vehicle to use.
VISUAL INSPECTION BEFORE WATER LEAK
TESTS
Verify that floor and body plugs are in place, body
drains are clear, and body components are properly
aligned and sealed. If component alignment or seal-
ing is necessary, refer to the appropriate section of
this group for proper procedures.
WATER LEAK TESTS
WARNING: DO NOT USE ELECTRIC SHOP LIGHTS
OR TOOLS IN WATER TEST AREA. PERSONAL
INJURY CAN RESULT.When the conditions causing a water leak have
been determined, simulate the conditions as closely
as possible.
²If a leak occurs with the vehicle parked in a
steady light rain, flood the leak area with an open-
ended garden hose.
²If a leak occurs while driving at highway speeds
in a steady rain, test the leak area with a reasonable
velocity stream or fan spray of water. Direct the
spray in a direction comparable to actual conditions.
²If a leak occurs when the vehicle is parked on an
incline, hoist the end or side of the vehicle to simu-
late this condition. This method can be used when
the leak occurs when the vehicle accelerates, stops or
turns. If the leak occurs on acceleration, hoist the
front of the vehicle. If the leak occurs when braking,
hoist the back of the vehicle. If the leak occurs on left
turns, hoist the left side of the vehicle. If the leak
occurs on right turns, hoist the right side of the vehi-
cle. For hoisting recommendations refer to Group 0,
Lubrication and Maintenance, General Information
section.
WATER LEAK DETECTION
To detect a water leak point-of-entry, do a water
test and watch for water tracks or droplets forming
on the inside of the vehicle. If necessary, remove inte-
rior trim covers or panels to gain visual access to the
leak area. If the hose cannot be positioned without
being held, have someone help do the water test.
NSBODY 23 - 23

may be necessary to use a soldering gun to melt
the newly applied material. Do not over heat the
affected area, damage to the exterior of the trim
panel may occur.
(4) Allow the repaired area to cool and verify the
repair.
(5) Install trim panel.
REMOVAL AND INSTALLATION
A-PILLAR LOWER EXTENSION TRIM
REMOVAL
(1) Remove instrument panel side cover.
(2) Remove screw holding A-pillar extension to
door hinge pillar.
(3) Remove A-pillar extension trim from vehicle
(Fig. 1).
INSTALLATION
(1) Place A-pillar extension trim in position on
vehicle.
(2) Install screw to hold A-pillar extension to door
hinge pillar.
(3) Install instrument panel side cover.
A-PILLAR TRIM PANEL
REMOVAL
(1) Disengage hidden clips holding A-pillar trim
panel to A-pillar (Fig. 2).
(2) Remove A-pillar trim from vehicle.
INSTALLATION
(1) Position foot on A-pillar trim panel into instru-
ment panel top cover channel.
(2) Position A-pillar trim in vehicle.
(3) Align locator pins.
(4) Engage hidden clips.
COWL COVER
WARNING: No fingers or tools should be put under
the cowl cover while the wiper motor is operating.
REMOVAL
(1) Remove wiper arms. Refer to Group 8K, Wind-
shield Wipers and Washers for proper procedures.
(2) Remove screws holding lower area of cowl cover
to wiper module (Fig. 3).
(3) Disengage quarter turn fasteners holding outer
ends of cowl cover to wiper module.
(4) Release hood latch and open hood.
(5) Remove wing nuts holding front of cowl cover
to wiper module.
(6) Close hood. Do not latch. Remove outboard
screws. (Fig. 4).
(7) Lift cowl cover upward enough to gain access to
right washer hose.
(8) D
isconnect washer hose from right washer nozzle.
(9) Close hood. Do not latch.
(10) Remove cowl cover from vehicle.
INSTALLATION
For installation, reverse the above procedures.
COWL TRIM
REMOVAL
(1) Remove door sill plate.
(2) Disengage hidden clips holding cowl trim to
cowl panel (Fig. 5).
(3) Remove cowl trim from vehicle.
Fig. 1 A-pillar Lower Extension Trim
Fig. 2 A-pillar Trim
NSBODY 23 - 25
SERVICE PROCEDURES (Continued)

(2) If equipped, remove pop-rivets holding molding
edge to wheelhouse lip.
(3) Pull stick-on molding from painted surface.
(4) Remove adhesive tape residue from painted
surface of vehicle. Use a 3M Scotch-BriteyMolding
Adhesive and Stripe Removal Disc, or equivalent, to
clean adhesive residue from painted surfaces. These
products are available from automotive paint suppli-
ers. Refer to instructions supplied with the specific
product for proper usage.
INSTALLATION
Refer to (Fig. 129), (Fig. 130), (Fig. 131), (Fig. 132)
or (Fig. 133) for proper location of fasteners to hold
the molding to the wheelhouse lip and rocker panels.
(1) If molding is to be reused;
(a) Remove tape residue from molding.
(b) Clean back of molding with MopartSuper
Kleen, or equivalent.
(c) Wipe molding dry with lint free cloth.
(d) Apply a single coat of MopartTPO Molding
Prep to tape side of molding and allow to dry thor-
oughly.
(e) Apply new body side molding (two sided
adhesive) tape to back of molding.
(2) Clean body surface with MopartSuper Kleen,
or equivalent. Wipe surface dry with lint free cloth.(3) Remove protective cover from tape on back of
molding.
(4) Apply molding to body from front to rear,
inserting locator pins into hole in body panel.
(5) Using a roller tool, roll molding onto body
panel with enough force to assure adhesion. Do not
apply excessive force, or damage to body panels may
result.
(6) Install pop-rivets to hold molding edge to
wheelhouse lip, if necessary.
SUN VISOR
All vehicles with driver and passenger side airbags
must have a colored coded five Bullet point airbag
warning label applied to the sun visor, verify label
availability and ensure the label is installed.
REMOVAL
(1) Disengage sun visor from center support.
(2) Remove screws attaching sun visor to roof
header (Fig. 134).
(3) Remove sun visor from roof.
(4) If equipped, disconnect illuminated vanity mir-
ror wire connector from body harness.
(5) Remove sun visor from vehicle.
Fig. 129 Body Side Moldings ± Base
23 - 76 BODYNS
REMOVAL AND INSTALLATION (Continued)

HEATING AND AIR CONDITIONING
CONTENTS
page page
FRONT HEATING AND AIR CONDITIONING
SYSTEM............................... 1REAR HEATING AND AIR CONDITIONING
SYSTEM.............................. 41
FRONT HEATING AND AIR CONDITIONING SYSTEM
INDEX
page page
GENERAL INFORMATION
INTRODUCTION......................... 2
SAFETY PRECAUTIONS AND WARNINGS...... 2
DESCRIPTION AND OPERATION
A/C PRESSURE TRANSDUCER.............. 2
A/C SERVICE PORTS..................... 2
AIR DISTRIBUTION DUCTS................. 2
COMPRESSOR HIGH-PRESSURE RELIEF
VALVE................................ 3
CONDENSATE DRAIN..................... 3
ENGINE COOLING SYSTEM REQUIREMENTS . . 3
EVAPORATOR PROBE..................... 3
HANDLING TUBING AND FITTINGS........... 3
HVAC CONTROL MODULE................. 4
REAR BLOWER SPEED SWITCH............ 3
SIDE DOOR HEATER A/C OUTLETS.......... 4
SIDE WINDOW DEMISTER................. 4
SYSTEM AIRFLOW....................... 4
SYSTEM OIL LEVEL...................... 5
DIAGNOSIS AND TESTING
A/C PERFORMANCE TEST................ 12
A/C PRESSURE TRANSDUCER............. 12
ACTUATOR CALIBRATION/DIAGNOSTICS AND
COOLDOWN TEST...................... 6
BLOWER MOTOR AND WHEEL ASSEMBLY.... 13
COMPRESSOR CLUTCH/COIL.............. 13
COMPRESSOR NOISE DIAGNOSIS.......... 13
EXPANSION VALVE...................... 13
HEATER PERFORMANCE TEST............ 15
HVAC CONTROL DIAGNOSTIC CONDITIONS . . . 9
SYSTEM CHARGE LEVEL TEST............ 16SERVICE PROCEDURES
CHARGING REFRIGERANT SYSTEM........ 17
EVACUATING REFRIGERANT SYSTEM....... 18
R-134a REFRIGERANT................... 16
STICKING HVAC CONTROL MODULE PUSH
BUTTONS............................ 19
SYSTEM LEAK CHECKING................ 19
THERMOCOUPLE PROBE................. 19
REMOVAL AND INSTALLATION
A/C PRESSURE TRANSDUCER............. 20
A/C SERVICE PORTS.................... 20
BLEND-AIR DOOR ACTUATOR............. 20
BLOWER MOTOR AND WHEEL ASSEMBLY.... 21
BLOWER MOTOR RESISTOR BLOCK........ 21
BLOWER MOTOR WHEEL................. 22
COMPRESSOR CLUTCH/COIL.............. 23
COMPRESSOR......................... 23
CONDENSER ASSEMBLY................. 25
DISCHARGE LINE....................... 26
EVAPORATOR PROBE.................... 27
EXPANSION VALVE...................... 28
FILTER-DRIER ASSEMBLY................. 28
HEATER A/C UNIT HOUSING............... 29
HEATER CORE......................... 30
HEATER HOSES........................ 31
LIQUID LINE........................... 32
MODE DOOR ACTUATOR................. 32
RECIRC DOOR ACTUATOR................ 34
SIDE WINDOW DEMISTER DUCTS.......... 33
SUCTION LINE.......................... 33
DISASSEMBLY AND ASSEMBLY
HEATER A/C UNIT RECONDITION........... 34
NSHEATING AND AIR CONDITIONING 24 - 1

GENERAL INFORMATION
INTRODUCTION
Both the heater and the heater/air conditioning
systems share many of the same components. This
group will deal with both systems together when
component function is common, and separately when
they are not.
For proper operation of the instrument panel con-
trols, refer to the Owner's Manual provided with the
vehicle.
All vehicles are equipped with a common A/C-
heater unit housing assembly. When the vehicle has
only a heater system, the evaporator and recirculat-
ing air door are omitted.
An optional zone control HVAC unit is available.
This unit has dual blend-air doors that can be regu-
lated independently of each other. The temperature
setting can be different from driver's side to passen-
ger side. There is also a rear (aux.) heating and A/C
system available when the vehicle is equipped with
zone control.
SAFETY PRECAUTIONS AND WARNINGS
WARNING: WEAR EYE PROTECTION WHEN SER-
VICING THE AIR CONDITIONING REFRIGERANT
SYSTEM. SERIOUS EYE INJURY CAN RESULT
FROM EYE CONTACT WITH REFRIGERANT. IF EYE
CONTACT IS MADE, SEEK MEDICAL ATTENTION
IMMEDIATELY.
DO NOT EXPOSE REFRIGERANT TO OPEN
FLAME. POISONOUS GAS IS CREATED WHEN
REFRIGERANT IS BURNED. AN ELECTRONIC TYPE
LEAK DETECTOR IS RECOMMENDED.
LARGE AMOUNTS OF REFRIGERANT RELEASED
IN A CLOSED WORK AREA WILL DISPLACE THE
OXYGEN AND CAUSE SUFFOCATION.
THE EVAPORATION RATE OF REFRIGERANT AT
AVERAGE TEMPERATURE AND ALTITUDE IS
EXTREMELY HIGH. AS A RESULT, ANYTHING THAT
COMES IN CONTACT WITH THE REFRIGERANT
WILL FREEZE. ALWAYS PROTECT SKIN OR DELI-
CATE OBJECTS FROM DIRECT CONTACT WITH
REFRIGERANT. R-134a SERVICE EQUIPMENT OR
VEHICLE A/C SYSTEM SHOULD NOT BE PRES-
SURE 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 PROPERTY
DAMAGE.
ANTIFREEZE IS AN ETHYLENE GLYCOL BASE
COOLANT AND IS HARMFUL IF SWALLOWED ORINHALED. SEEK MEDICAL ATTENTION IMMEDI-
ATELY IF SWALLOWED OR INHALED. DO NOT
STORE IN OPEN OR UNMARKED CONTAINERS.
WASH SKIN AND CLOTHING THOROUGHLY AFTER
COMING IN CONTACT WITH ETHYLENE GLYCOL.
KEEP OUT OF REACH OF CHILDREN AND PETS.
DO NOT OPEN A COOLING SYSTEM WHEN THE
ENGINE IS AT RUNNING TEMPERATURE. PER-
SONAL INJURY CAN RESULT.
CAUTION: The engine cooling system is designed
to develop internal pressure of 97 to 123 kPa (14 to
18 psi). Allow the vehicle to cool a minimum of 15
minutes before opening the cooling system. Refer
to Group 7, Cooling System.
DESCRIPTION AND OPERATION
AIR DISTRIBUTION DUCTS
The air distribution ducts for the A/C, Heater,
Defroster, and Second Seating Air Distribution are
not serviceable in vehicle. The procedures for service
of these ducts are covered in Group 8E, Instrument
Panel and Gauges.
The only ducts that are serviceable in the vehicle
are the side window demister ducts and the ducts
that feed the front door outlets for the first rear pas-
senger(s) seating. To service the door ducts refer to
Group 23, Body.
A/C PRESSURE TRANSDUCER
The A/C Pressure Transducer (Fig. 1) monitors the
refrigerant gas pressure on the high side of the sys-
tem. The transducer is located on the liquid line. The
pressure transducer turns off the voltage to the com-
pressor clutch coil when refrigerant gas pressure
drops to levels that could damage the compressor.
The transducer also is used to adjust condenser fan
speeds and will turn off compressor at high refriger-
ant pressures. The pressure transducer is a sealed
factory calibrated unit. It must be replaced if defec-
tive. O-ring replacement is required whenever the
pressure transducer is serviced. Be sure to use the
O-ring specified for the transducer.
A/C SERVICE PORTS
The A/C service port valve cores are located within
the A/C lines (Fig. 2). The High Side (Discharge)
valve service port is located on the liquid line near
the right frame rail. The Low Side (Suction) valve
service port is located on the suction line near the
compressor.
24 - 2 HEATING AND AIR CONDITIONINGNS

probe will drop the temperature 7ÉC (20ÉF) in two
minutes. If the Evaporator Probe is found to be
faulty, check that the sensor is positioned in the
evaporator fins properly. If not, correct and repeat
test. If OK, replace the evaporator probe.
Once the repairs are completed, repeat the Calibra-
tion Diagnostic and Cooldown test. Repeating the
test is necessary to clear the fault codes.
A/C PERFORMANCE TEST
The air conditioning system is designed to remove
heat and humidity from the air entering the passen-
ger compartment. The evaporator, located in the
heater A/C unit, is cooled to temperatures near the
freezing point. As warm damp air passes over the
fins in the evaporator, moisture in the air condenses
to water, dehumidifying the air. Condensation on the
evaporator fins reduces the evaporators ability to
absorb heat. During periods of high heat and humid-
ity, an air conditioning system will be less effective.
With the instrument control set to RECIRC, only air
from the passenger compartment passes through the
evaporator. As the passenger compartment air dehu-
midifies, A/C performance levels rise.
PERFORMANCE TEST PROCEDURE
Review Safety Precautions and Warnings in this
group before proceeding with this procedure. Air tem-
perature in test room and on vehicle must be 21É C
(70ÉF) minimum for this test.
NOTE: When connecting the service equipment
coupling to the line fitting, verify that the valve of
the coupling is fully closed. This will reduce the
amount of effort required to make the connection.
(1) Connect a tachometer and manifold gauge set.
(2) Set control to A/C, RECIRC, and PANEL, tem-
perature lever on full cool and blower on high.
(3) Start engine and hold at 1000 rpm with A/C
clutch engaged.(4) Engine should be warmed up with doors and
windows closed.
(5) Insert a thermometer in the left center A/C
outlet and operate the engine for five minutes. The
A/C clutch may cycle depending on ambient condi-
tions.
(6) With the A/C clutch engaged, compare the dis-
charge air temperature to the A/C Performance Tem-
peratures table.
(7) If the discharge air temperature fails to meet
the specifications in the performance temperature
chart. Refer to the Refrigerant Service Procedures for
further diagnosis.
A/C PRESSURE TRANSDUCER
The work area temperature must not be below
10ÉC (50ÉF) to test the compressor clutch circuit.
Before starting to test the transducer ensure that the
wire connector is clean of corrosion and connected
properly.
(1) With gear selector in park or neutral and park
brake set, start engine and allow to idle.
(2) Install scan tool (DRB):
²Go to main menu
²Select stand alone scan tool (DRB)
²Select refer to the proper year diagnostics
²Select climate control
²Select sensor display
²Select A/C high side volts
For A/C system to operate a voltage between .451
(Low Pressure Cutout) to 4.519 (High Pressure Cut-
out is required. Voltages outside this range indicate a
low or high pressure condition andwill notallow
the compressor to cycle.
Refer to the A/C Pressure Transducer Voltage table
for the appropriate condition(s):
A/C PERFORMANCE TEMPERATURES
AMBIENT TEMPERATURE 21ÉC
(70ÉF)26.5ÉC
(80ÉF)32ÉC
(90ÉF)37ÉC
(100ÉF)43ÉC
(110ÉF)
AIR TEMPERATURE AT LEFT
CENTER PANEL OUTLET1-8ÉC
(34-46ÉF)3-9ÉC
(37-49ÉF)4-10ÉC
(39-50ÉF)6-11ÉC
(43-52ÉF)7-18ÉC
(45-65ÉF)
COMPRESSOR DISCHARGE
PRESSURE AFTER THE FILTER
DRIER1034-1724
kPa
(150-250
PSI)1517-2275
kPa
(220-330
PSI)1999-2620
kPa
(290-380
PSI)2068-2965
kPa
(300-430
PSI)2275-3421
kPa
(330-496
PSI)
EVAPORATOR SUCTION
PRESSURE103-207 kPa
(15-30 PSI)117-221 kPa
(17-32 psi)138-241 kPa
(20-35 PSI)172-269 kPa
(25-39 PSI)207-345 kPa
(30-50 PSI)
24 - 12 HEATING AND AIR CONDITIONINGNS
DIAGNOSIS AND TESTING (Continued)

BLOWER MOTOR AND WHEEL ASSEMBLY
VIBRATION AND/OR NOISE DIAGNOSIS
The blower speed switch, in conjunction with the
resistor block, supplies the blower motor with varied
voltage.
CAUTION: Stay clear of the blower motor and resis-
tor block (Hot). Do not operate the blower motor
with the resistor block removed from the heater A/C
housing.
Refer to the Blower Motor Vibration/Noise chart in
this section for diagnosis.
COMPRESSOR NOISE DIAGNOSIS
Excessive noise while the A/C is being used, can be
caused by loose mounts, loose clutch, or high operat-
ing pressure. Verify compressor drive belt condition,
proper refrigerant charge and head pressure before
compressor repair is performed.
If the A/C drive belt slips at initial start-up, it does
not necessarily mean the compressor has failed.
With the close tolerances of a compressor it is pos-
sible to experience a temporary lockup. The longer
the A/C system is inactive, the more likely the condi-
tion to occur.
This condition is the result of normal refrigerant
movement within the A/C system caused by temper-
ature changes. The refrigerant movement may wash
the oil out of the compressor.
COMPRESSOR CLUTCH/COIL
The air conditioning compressor clutch electrical
circuit is controlled by the Powertrain Control Mod-
ule. It is located in the engine compartment outboard
of the battery.If the compressor clutch does not engage verify
refrigerant charge.
If the compressor clutch still does not engage check
for battery voltage at the pressure transducer located
on the liquid line. If voltage is not detected, refer to:
²Group 8W, Wiring diagrams.
²Powertrain Diagnostic Procedures manual for
diagnostic information.
If voltage is detected at the pressure transducer,
connect pressure transducer and check for battery
voltage between the compressor clutch connector ter-
minals.
If voltage is detected, perform A/C Clutch Coil
Tests.
TESTS
(1) Verify battery state of charge. (Test indicator in
battery should be green).
(2) Connect an ampmeter (0-10 ampere scale) in
series with the clutch coil terminal. Use a voltmeter
(0-20 volt scale) with clip leads measuring voltage
across the battery and A/C clutch.
(3) With A/C control in A/C mode and blower at
low speed, start the engine and run at normal idle.
(4) The A/C clutch should engage immediately and
the clutch voltage should be within two volts of the
battery voltage. If the A/C clutch does not engage,
test the fuse.
(5) The A/C clutch coil is acceptable if the current
draw is 2.0 to 3.7 amperes at 11.5-12.5 volts at clutch
coil. This is with the work area temperature at 21ÉC
(70ÉF). If voltage is more than 12.5 volts, add electri-
cal loads by turning on electrical accessories until
voltage reads below 12.5 volts.
(6) If coil current reads zero, the coil is open and
should be replaced. If the ammeter reading is 4
amperes or more, the coil is shorted and should be
replaced. If the coil voltage is not within two volts of
the battery voltage, test clutch coil feed circuit for
excessive voltage drop.
EXPANSION VALVE
NOTE: Special effort must be used to keep all
R-134a system components moisture-free. Moisture
in the oil is very difficult to remove and will cause a
reliability problem with the compressor.
TESTS
NOTE: Expansion valve tests should be performed
after compressor tests.
Review Safety Precautions and Warnings in this
group. The work area and vehicle temperature must
A/C PRESSURE TRANSDUCER VOLTAGE
VOLTAGE CONDITION
0 TRANSDUCER FAULTY
OR NO VOLTAGE FROM
PCM
.150 TO .450 TRANSDUCER
GOOD/LOW PRESSURE
CUTOUT CONDITION
.451 TO 4.519 NORMAL OPERATING
CONDITION
4.520 TO 4.850 TRANSDUCER
GOOD/HIGH
PRESSURE CUTOUT
CONDITION
5 TRANSDUCER FAULTY
NSHEATING AND AIR CONDITIONING 24 - 13
DIAGNOSIS AND TESTING (Continued)

be 21ÉC to 27ÉC (70ÉF to 85ÉF). To test the expansion
valve:
NOTE: Liquid CO2 is required to test the expansion
valve. It is available from most welding supply facil-
ities. CO2 is also available from companies which
service and sell fire extinguishers.
(1) Connect a charging station or manifold gauge
set to the refrigerant system service ports. Verify the
refrigerant charge level.
(2) Close all doors, windows and vents to the pas-
senger compartment.
(3) Set heater A/C control to A/C, full heat,
FLOOR, and high blower.
(4) Start the engine and allow to idle (1000 rpm).
After the engine has reached running temperature,
allow the passenger compartment to heat up. This
will create the need for maximum refrigerant flow
into the evaporator.
(5) If the refrigerant charge is sufficient, discharge
(high pressure) gauge should read 965 to 1655 kPa
(140 to 240 psi). Suction (low pressure) gauge should
read 140 kPa to 207 kPa (20 psi to 30 psig). If system
cannot achieve proper pressure readings, replace the
expansion valve. If pressure is correct, proceed with
test.
WARNING: PROTECT SKIN AND EYES FROM CON-
TACTING CO2 PERSONAL INJURY CAN RESULT.
(6) If suction side low pressure is within specified
range, freeze the expansion valve control head for 30
seconds. Use a super cold substance (liquid CO2).Do
not spray R-134a or R-12 Refrigerant on the
expansion valve for this test.Suction side low
pressure should drop by 10 psi. If not, replace expan-
sion valve.
(7) Allow expansion valve to thaw. The low pres-
sure gauge reading should stabilize at 140 kPa to
240 kPa (20 psi to 30 psig). If not, replace expansion
valve.
(8) When expansion valve test is complete, test
A/C overall performance. Remove all test equipment
before returning vehicle to use.
HEATER PERFORMANCE TEST
PRE-DIAGNOSTIC PREPARATIONS
Review Safety Precautions and Warnings in this
group before performing the following procedures.
Check the coolant level, drive belt tension, vacuum
line connections, radiator air flow and fan operation.
Start engine and allow to warm up to normal tem-
perature.WARNING: DO NOT REMOVE RADIATOR CAP
WHEN ENGINE IS HOT, PERSONAL INJURY CAN
RESULT.
If vehicle has been run recently, wait 15 minutes
before removing cap. Place a rag over the cap and
turn it to the first safety stop. Allow pressure to
escape through the overflow tube. When the system
stabilizes, remove the cap completely.
MAXIMUM HEATER OUTPUT: TEST AND
ACTION
Engine coolant is provided to the heater system by
two 16 mm (5/8 inch inside diameter) heater hoses.
With engine idling at normal running temperature,
set the control to maximum heat, floor, and high
blower setting. Using a test thermometer, check the
air temperature coming from the floor outlets, refer
to Temperature Reference Table.
If the floor outlet air temperature is insufficient,
refer to Group 7, Cooling Systems for specifications.
Both heater hoses should be HOT to the touch (cool-
ant return hose should be slightly cooler than the
supply hose). If coolant return hose is much cooler
than the supply hose, locate and repair engine cool-
ant flow obstruction in heater system.
POSSIBLE LOCATIONS OR CAUSE OF
OBSTRUCTED COOLANT FLOW
(1) Pinched or kinked heater hoses.
(2) Improper heater hose routing.
(3) Plugged heater hoses or supply and return
ports at cooling system connections, refer to Group 7,
Cooling System.
(4) Plugged heater core.
(5) Air locked heater core.
(6) If coolant flow is verified and outlet tempera-
ture is insufficient, a mechanical problem may exist.
POSSIBLE LOCATION OR CAUSE OF
INSUFFICIENT HEAT
(1) Obstructed cowl air intake.
(2) Obstructed heater system outlets.
(3) Blend-air door not functioning properly.
TEMPERATURE REFERENCE TABLE
AMBIENT
TEMPERATUREMINIMUM FLOOR
OUTLET TEMPERATURE
CELSIUS FAHRENHEIT CELSIUS FAHRENHEIT
15.5É 60É 62.2É 144É
21.1É 70É 63.8É 147É
26.6É 80É 65.5É 150É
32.2É 90É 67.2É 153É
NSHEATING AND AIR CONDITIONING 24 - 15
DIAGNOSIS AND TESTING (Continued)