oil pressure CHRYSLER VOYAGER 1996 Service Manual

The high pressure service port is located on the liq-
uid line near the strut tower. The low pressure ser-
vice port is located on the suction line near the
compressor manifold.
When servicing a system, it is required that an air
conditioning charging recovery/recycling machine be
used (Fig. 8). Contact an automotive service equip-
ment supplier for proper equipment. Refer to the
operating instructions provided with the equipment
for proper operation.
A manifold gauge set (Fig. 9) must also be used in
conjunction with the charging and/or recovery/recy-
cling device. Only use gauges that have not been
used for R-12. The service hoses on the gauge set
should have manual (turn wheel) or automatic back
flow valves at the service port connector ends. This
will prevent refrigerant R-134a from being released
into the atmosphere.
R-134a refrigerant requires a special type of com-
pressor oil. When adding oil, make sure to use the oil
that is specified on the under hood label.
Due to the different characteristics of R-134a it
requires all new service procedures.
The use of R-134a will have a positive environmen-
tal impact due to it's zero ozone depletion and low
global warming impact.
CHARGING REFRIGERANT SYSTEM
CAUTION: Do not overcharge refrigerant system,
as excessive compressor head pressure can cause
noise and system failure.
After the system has been tested for leaks and
evacuated, a refrigerant (R-134a) charge can be
injected into the system.
Charge Determination Chart
Fig. 8 Refrigerant Recovery/Recycling Station
(Typical)
NSHEATING AND AIR CONDITIONING 24 - 17
SERVICE PROCEDURES (Continued)

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 manifold gauge set.
(2) Measure refrigerant (refer to capacities) and
heat to 52ÉC (125ÉF) with the charging station. Refer
to the instructions provided with the equipment
being used.
REFRIGERANT CAPACITIES
²Without Rear A/C = .96 kg (34 oz. or 2.13lb.)
²With Rear A/C = 1.36 kg (48 oz. or 3.00 lb.)
(3) Open the suction and discharge valves. Open
the charge valve to allow the heated refrigerant to
flow into the system. When the transfer of refriger-
ant has stopped, close the suction and discharge
valve.
(4) If all of the charge did not transfer from the
dispensing device, run engine at a high idle (1400
rpm). Set the A/C control to A/C, low blower speed,
and open windows. If the A/C compressor does not
engage, test the compressor clutch control circuit and
correct any failure. Refer to Group 8W, Wiring Dia-
grams.
(5) Open the suction valve to allow the remaining
refrigerant to transfer to the system.
WARNING: TAKE CARE NOT TO OPEN THE DIS-
CHARGE (HIGH-PRESSURE) VALVE AT THIS TIME.(6) Close all valves and test the A/C system perfor-
mance.
(7) Disconnect the charging station or manifold
gauge set. Install the service port caps.
EVACUATING REFRIGERANT SYSTEM
NOTE: Special effort must be used to prevent mois-
ture from entering the A/C system oil. Moisture in
the oil is very difficult to remove and will cause a
reliability problem with the compressor.
If a compressor designed to use R-134a refrigerant
is left open to the atmosphere for an extended period
of time. It is recommended that the refrigerant oil be
drained and replaced with new oil or a new compres-
sor be used. This will eliminate the possibility of con-
taminating the refrigerant system.
If the refrigerant system has been open to the
atmosphere, it must be evacuated before the system
can be filled. Moisture and air mixed with the refrig-
erant will raise the compressor head pressure above
acceptable operating levels. This will reduce the per-
formance of the air conditioner and damage the com-
pressor. Moisture will boil at near room temperature
when exposed to vacuum. To evacuate the refrigerant
system:
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 suitable charging station, refrigerant
recovery machine, and a manifold gauge set with
vacuum pump (Fig. 10).
(2) Open the suction and discharge valves and
start the vacuum pump. The vacuum pump should
run a minimum of 45 minutes prior to charge to
Fig. 9 Manifold Gauge Set- Typical
Fig. 10 Refrigerant Recovery Machine Hookup
24 - 18 HEATING AND AIR CONDITIONINGNS
SERVICE PROCEDURES (Continued)

eliminate all moisture in system. When the suction
gauge reads -88 kPa (- 26 in. Hg) vacuum or greater
for 45 minutes, close all valves and turn off vacuum
pump. If the system fails to reach specified vacuum,
the refrigerant system likely has a leak that must be
corrected. If the refrigerant system maintains speci-
fied vacuum for at least 30 minutes, start the vac-
uum pump, open the suction and discharge valves.
Then allow the system to evacuate an additional 10
minutes.
(3) Close all valves. Turn off and disconnect the
vacuum pump.
(4) The refrigerant system is prepared to be
charged with refrigerant.
THERMOCOUPLE PROBE
To diagnose the A/C system, a temperature probe is
required to measure liquid line temperature. The
clamp-on type K probe shown in this manual is avail-
able through the Chrysler Professional Service
Equipment (PSE) program. This probe is compatible
with temperature-measuring instruments that accept
Type K Thermocouples and have a miniature connec-
tor input. Other temperature probes are available
through aftermarket sources. All references in this
manual will reflect the use of the probe made avail-
able through the Professional Service Equipment pro-
gram.
In order to use the temperature probe, a digital
thermometer will be required. If a digital thermome-
ter is not available, an adapter is available through
the Professional Service Equipment program. It can
convert any standard digital multimeter into a ther-
mometer. This adapter is designed to accept any
standard K-type thermocouple.
If a digital multimeter is not available, it to can be
ordered through Professional Service Equipment pro-
gram.
STICKING HVAC CONTROL MODULE PUSH
BUTTONS
To service HVAC control module push buttons that
are sticking, spray between the buttons with Mopart
MP-50. The MP-50 is a all purpose lubricant for
mechanical and electrical uses. After spraying around
the push buttons wipe any excess off the radio bezel
and HVAC control module push buttons. Operate the
buttons to ensure that they are operating freely.
SYSTEM LEAK CHECKING
WARNING: R-134a SERVICE EQUIPMENT OR VEHI-
CLE A/C SYSTEM SHOULD NOT BE PRESSURE
TESTED OR LEAK TESTED WITH COMPRESSED
AIR. SOME MIXTURES OF AIR/R-134a HAVE BEEN
SHOWN TO BE COMBUSTIBLE AT ELEVATEDPRESSURES. THESE MIXTURES ARE POTENTIALLY
DANGEROUS AND MAY RESULT IN FIRE OR
EXPLOSION CAUSING INJURY OR PROPERTY
DAMAGE.
If the A/C system is not cooling properly, determine
if the refrigerant system is fully charged with
R-134a. This is accomplished by performing a system
Charge Level-Check or Fill. If while performing this
test A/C liquid line pressure is less than 207 kPa (30
psi) proceed to Empty Refrigerant System Leak Test.
If liquid line pressure is greater than 207 kPa (30
psi) proceed to low refrigerant level leak test. If the
refrigerant system is empty or low in refrigerant
charge, a leak at any line fitting or component seal is
likely. A review of the fittings, lines and components
for oily residue is an indication of the leak location.
To detect a leak in the refrigerant system, perform
one of the following procedures as indicated by the
symptoms.
WARNING: AVOID BREATHING A/C REFRIGERANT
AND LUBRICANT VAPOR OR MIST. EXPOSURE MAY
IRRITATE EYES, NOSE AND THROAT. USE ONLY
APPROVED SERVICE EQUIPMENT MEETING SAE
REQUIREMENTS TO DISCHARGE R-134a SYSTEM.
IF ACCIDENTAL SYSTEM DISCHARGE OCCURS,
VENTILATE WORK AREA BEFORE RESUMING SER-
VICE.
EMPTY REFRIGERANT SYSTEM LEAK TEST
(1) Evacuate the refrigerant system to the lowest
degree of vacuum possible (about 28 in Hg.). Deter-
mine if the system holds a vacuum for 15 minutes. If
vacuum is held, a leak is probably not present. If sys-
tem will not maintain vacuum level, proceed with
this procedure.
(2) Prepare a .284 Kg. (10 oz.) refrigerant charge
to be injected into the system.
(3) Connect and dispense .284 Kg. (10 oz.) of
refrigerant into the evacuated refrigerant system.
(4) Proceed to step two of Low Refrigerant Level
Leak Test.
LOW REFRIGERANT LEVEL LEAK TEST
(1) Determine if there is any (R-134a) refrigerant
in the system. Use the scan tool (DRB) under the
menu Systems Sensors±A/C Pressure test or pressure
gauge liquid line temperature partial charge check.
See system charge level check or fill for procedure.
(2) Position the vehicle in a wind free work area.
This will aid in detecting small leaks.
(3) Bring the refrigerant system up to operating
temperature and pressure. This is done by allowing
the engine to run for five minutes with the system
set to the following:
NSHEATING AND AIR CONDITIONING 24 - 19
SERVICE PROCEDURES (Continued)

²Transaxle in Park
²Engine Idling at 700 rpm
²A/C Controls Set in 100 percent outside air
²Full Panel Mode
²Blower motor ON HIGH
²A/C in the ON position
²Front Windows Open.
²Rear Air Off (If Equipped)
CAUTION: A leak detector designed for R-12 refrig-
erant will not detect leaks in a R-134a refrigerant
system.
(4) Shut off the vehicle and wait 2 to 7 minutes.
Then use an Electronic Leak Detector that is
designed to detect R-134a type refrigerant and search
for leaks. Fittings, lines, or components that appear
to be oily usually indicates a refrigerant leak. To
inspect the evaporator core for leaks, insert the leak
detector probe into the recirculating air door opening
or a heat duct.
If a thorough leak check has been completed with-
out indication of a leak, proceed to System Charge
Level-Check or Fill.
REMOVAL AND INSTALLATION
A/C PRESSURE TRANSDUCER
REMOVAL
(1) Disconnect the wire connector at the pressure
transducer.
(2) Using an open end wrench, remove the trans-
ducer from the liquid line (Fig. 11).
INSTALLATION
(1) Replace transducer O-ring.
(2) For installation, reverse the above procedures.
A/C SERVICE PORTS
WARNING: THE REFRIGERATION SYSTEM MUST
BE COMPLETELY EMPTY BEFORE PROCEEDING
WITH THIS OPERATION.
The High Side service port is serviceable, the Low
Side is not serviceable.
REMOVAL
(1) Disconnect the battery negative cable.
(2) Recover A/C system refrigerant.
(3) Unscrew the High Side service port from the
liquid line.
(4) Remove O-ring
INSTALLATION
For installation, reverse the above procedures.
²Install new O-ring.
²Evacuate and recharge A/C system.
BLEND-AIR DOOR ACTUATOR
REMOVAL
The air conditioning system can be equipped with
either a standard, single blend-air door actuator, or it
can be equipped with dual actuators. The dual sys-
tem has separate blend-air controls. This allows for
separate control of the driver's side air, and the pas-
senger side air (Fig. 12).
(1) Remove the lower left side steering column
cover. Refer to Group 8E, Instrument Panel and Sys-
tems.
(2) Remove ABS control module (Fig. 13).
(3) Remove blend-air actuator connector.
(4) Remove blend-air actuator (Fig. 14).
INSTALLATION
(1) For installation, reverse the above procedures.
Fig. 11 A/C Pressure Transducer Removal
Fig. 12 Side View Of HVAC With Actuators
24 - 20 HEATING AND AIR CONDITIONINGNS
SERVICE PROCEDURES (Continued)

EVAPORATOR AND 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.
REMOVAL
WARNING: THE REFRIGERANT SYSTEM MUST BE
EMPTY BEFORE PERFORMING THE FOLLOWING
OPERATION. THE ENGINE COOLING SYSTEM
MUST ALSO BE RELIEVED OF ALL PRESSURE.
(1) Remove right quarter trim panel and D-pillar
trim. Refer to Group 23, Body.
(2) Remove fan A/C distribution duct.
(3) Remove rear A/C unit.
(4) Remove blower scroll.
(5) Remove evaporator cover (Fig. 12).
(6) Remove the nut that mounts the refrigerant
plumbing block to the expansion valve (Fig. 13).
(7) Carefully pull the evaporator and expansion
valve straight out of unit (Fig. 14). Do not scratch
the sealing surfaces with the plumbing extension
tube pilots.
(8) Remove and discard the O-rings between the
plumbing extension and the expansion valve.
(9) Cover the plumbing extension sealing surface
to prevent contamination.
(10) Bring evaporator and expansion valve to a
clean work space.
(11) Remove two 1/4-20 Torx Head screws.
(12) Remove expansion valve.
(13) Measure and record the amount of residual oil
from the removed evaporator.
INSTALLATION
(1) Replace the O-rings.(2) Hold expansion valve against evaporator seal-
ing plate (do not scratch the sealing surface). Install
two screws and tighten to 1163 N´m (100630 inch
pounds) torque.
Fig. 11 Rear Heat-A/C UnitFig. 12 Evaporator Cover
Fig. 13 Expansion Valve
Fig. 14 Evaporator Removal
24 - 44 HEATING AND AIR CONDITIONINGNS
REMOVAL AND INSTALLATION (Continued)

REAR HEATER A/C BLOWER MOTOR
REMOVAL
(1) Remove the right quarter trim panel and D-pil-
lar trim. Refer to Group 23, Body for service proce-
dures.
(2) Remove (5) screws securing the blower motor
housing to the rear of the HVAC housing (one screw
located on evaporator cover) (Fig. 16).
(3) Twist motor out of scroll housing.
(4) Disconnect blower motor wiring connector.
INSTALLATION
For installation, reverse the above procedures.
REAR HEATER-A/C CONTROL ILLUMINATION BULB
REMOVAL
(1) Remove rear heater-A/C control from trim
panel.
(2) On the back of control opposite from the wire
connectors, locate the bulb socket lug.
(3) Rotate the socket counterclockwise and pull the
socket from the control.
INSTALLATION
For installation, reverse the above procedures.
Refer to Group 8L, Lamps for bulb usage.
REAR HEATER A/C UNIT
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.
REMOVAL
WARNING: ON VEHICLES EQUIPPED WITH REAR
A/C, THE REFRIGERANT SYSTEM MUST BE EMP-
TIED BEFORE PERFORMING THE FOLLOWING
OPERATION. THE ENGINE COOLING SYSTEM
MUST ALSO BE RELIEVED OF ALL PRESSURE.
(1) Using a refrigerant recovery machine, remove
refrigerant from the A/C system. Disconnect A/C
plumbing from rear heater A/C unit.
(2) Hoist vehicle.
(3) Remove A/C lines at lower floor pan flange
(Fig. 17).
(4) Remove (3) A/C unit floor mounting nuts (Fig.
18).
(5) Lower vehicle.
(6) Remove right quarter trim panel and D-pillar
trim (Fig. 8). Refer to Group 23, Body.
(7) Remove screws securing air distribution duct to
the rear wheel housing (Fig. 19).
Fig. 16 Blower Motor
Fig. 17 A/C Lines
Fig. 18 A/C Mounting
24 - 46 HEATING AND AIR CONDITIONINGNS
REMOVAL AND INSTALLATION (Continued)

HEATING AND AIR CONDITIONING
CONTENTS
page page
GENERAL INFORMATION
INTRODUCTION........................ 1
SAFETY PRECAUTIONS AND WARNINGS.... 2
DESCRIPTION AND OPERATION
A/C PRESSURE TRANSDUCER............ 2
A/C SERVICE PORTS.................... 2
AIR DISTRIBUTION DUCTS............... 2
COMPRESSOR......................... 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................ 3
SIDE DOOR HEATER A/C OUTLETS........ 4
SIDE WINDOW DEMISTER............... 4
SYSTEM AIRFLOW..................... 4
SYSTEM OIL LEVEL..................... 4
DIAGNOSIS AND TESTING
A/C PERFORMANCE TEST............... 11
A/C PRESSURE TRANSDUCER........... 11
ACTUATOR CALIBRATION/DIAGNOSTICS AND
COOLDOWN TEST..................... 5
BLOWER MOTOR AND WHEEL ASSEMBLY . 12
COMPRESSOR CLUTCH/COIL............ 12
COMPRESSOR NOISE DIAGNOSIS........ 12
EXPANSION VALVE.................... 14
HEATER PERFORMANCE TEST........... 14
HVAC CONTROL DIAGNOSTIC CONDITIONS . 9
SYSTEM CHARGE LEVEL TEST........... 15SERVICE PROCEDURES
CHARGING REFRIGERANT SYSTEM....... 17
EVACUATING REFRIGERANT SYSTEM..... 17
R-134a REFRIGERANT.................. 16
STICKING HVAC CONTROL MODULE PUSH
BUTTONS.......................... 18
SYSTEM LEAK CHECKING............... 19
THERMOCOUPLE PROBE............... 18
REMOVAL AND INSTALLATION
A/C PRESSURE TRANSDUCER........... 19
A/C SERVICE PORTS................... 19
BLEND-AIR DOOR ACTUATOR........... 20
BLOWER MOTOR AND WHEEL ASSEMBLY . 20
BLOWER MOTOR RESISTOR BLOCK...... 21
BLOWER MOTOR WHEEL............... 22
COMPRESSOR (2.5L TURBO DIESEL)..... 22
CONDENSER ASSEMBLY................ 23
DISCHARGE LINE..................... 23
EVAPORATOR PROBE.................. 24
EXPANSION VALVE.................... 25
FILTER-DRIER ASSEMBLY............... 26
HEATER A/C UNIT HOUSING............. 26
HEATER CORE........................ 26
HEATER HOSES....................... 28
LIQUID LINE......................... 28
MODE DOOR ACTUATOR................ 29
RECIRC DOOR ACTUATOR.............. 30
SIDE WINDOW DEMISTER DUCTS........ 29
SUCTION LINE........................ 29
DISASSEMBLY AND ASSEMBLY
HEATER A/C UNIT RECONDITION......... 30
GENERAL INFORMATION
INTRODUCTION
The Heater, or Heater and Air Conditioning sys-
tems 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 Heater
A/C 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.
NS/GSHEATING AND AIR CONDITIONING 24 - 1

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 OR
INHALED. 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 arenot 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. The High Side (Discharge) valve ser-
vice port is located on the liquid line near the right
strut tower. The Low Side (Suction) valve service
port is located on the suction line near the compres-
sor.
The High Side service port is a two piece port and
is serviceable. The Low Side service port is not ser-
viceable, and the suction line would have to be
replaced.
COMPRESSOR
The A/C compressor for the 2.5L Turbo Diesel, is
located on the front side of the engine block. It is
mounted to the engine block by four bolts. The com-
Fig. 1 A/C Pressure Transducer
24 - 2 HEATING AND AIR CONDITIONINGNS/GS
GENERAL INFORMATION (Continued)

pressor is driven off the back of the power steering
pump. A rubber flex coupling transfers the power from
the power steering pump to the compressor clutch.
COMPRESSOR HIGH-PRESSURE RELIEF VALVE
The High Pressure Relief Valve prevents damage
to the air conditioning system if excessive pressure
develops. Excessive pressure can be caused by con-
denser air flow blockage, refrigerant overcharge, or
air and moisture in the system.
The high pressure relief valve vents only a small
amount of refrigerant necessary to reduce system
pressure and then reseats itself. The majority of the
refrigerant is conserved in the system. The valve is
calibrated to vent at a pressure of 3450 to 4140 kPa
(500 to 600 psi). If a valve has vented a small
amount of refrigerant, it does not necessarily mean
the valve is defective.
The High Pressure Relief Valve is located on the
compressor manifold at the discharge passage.
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.
CONDENSATE DRAIN
Condensation from the evaporator housing is
drained through the dash panel and on to the
ground. This drain must be kept open to prevent
water from collecting in the bottom of the housing.
If the drain is blocked condensate cannot drain,
causing water to back up and spill into the passenger
compartment. It is normal to see condensate drain-
age below the vehicle.
ENGINE COOLING SYSTEM REQUIREMENTS
To maintain ample temperature levels from the
heating-A/C system, the cooling system must be in
proper working order. Refer to Group 0, Lubrication
and Maintenance or Group 7, Cooling System of this
manual.
The use of a bug screen is not recommended. Any
obstructions forward of the condenser can reduce the
effectiveness of the air conditioning system.
EVAPORATOR PROBE
The Evaporator probe is located on the HVAC. The
probe prevents evaporator freeze-up by signaling the
Powertrain Control Module to cycle the compressor
ON and OFF. The probe monitors the temperature of
the refrigerant after expansion.
The evaporator probe is inserted into the evapora-
tor between the coils. The probe is a sealed unit and
cannot be adjusted or repaired. It must be replaced if
found defective.
HANDLING TUBING AND FITTINGS
Kinks in the refrigerant tubing or sharp bends in
the refrigerant hose lines will greatly reduce the
capacity of the entire system. High pressures are pro-
duced in the system when it is operating. Extreme
care must be exercised to make sure that all connec-
tions are pressure tight. Dirt and moisture can enter
the system when it is opened for repair or replace-
ment of lines or components. The refrigerant oil will
absorb moisture readily out of the air. This moisture
will convert into acids within a closed system.
CAUTION: The system must be completely empty
before opening any fitting or connection in the
refrigeration system. Open fittings with caution
even after the system has been emptied. If any
pressure is noticed as a fitting is loosened,
retighten fitting and evacuate the system again.
A good rule for the flexible hose lines is to keep
the radius of all bends at least 10 times the diame-
ter of the hose. Sharper bends will reduce the flow
of refrigerant. The flexible hose lines should be
routed so they are at least 3 inches (80 mm) from
the exhaust manifold. Inspect all flexible hose lines
to make sure they are in good condition and prop-
erly routed.
The use of correct wrenches when making con-
nections is very important. Improper wrenches or
improper use of wrenches can damage the fittings.
The internal parts of the A/C system will remain
stable as long as moisture-free refrigerant and
refrigerant oil is used. Abnormal amounts of dirt,
moisture or air can upset the chemical stability.
This may cause operational troubles or even seri-
ous damage if present in more than very small
quantities.
When opening a refrigeration system, have every-
thing you will need to repair the system ready. This
will minimize the amount of time the system must
be opened. Cap or plug all lines and fittings as
soon as they are opened. This will help prevent the
entrance of dirt and moisture. All new lines and
components should be capped or sealed until they
are ready to be used.
All tools, including the refrigerant dispensing
manifold, the manifold gauge set, and test hoses
should be kept clean and dry.
HVAC CONTROL MODULE
The HVAC control module regulates the operation
of the various actuator motors. The actuator motors
are used to move the mode, blend- air, and recirc.
doors (Fig. 2).
The control module is included in the A/C control
head located on the instrument panel. The control
head includes the blower speed switch, rear wiper
NS/GSHEATING AND AIR CONDITIONING 24 - 3
DESCRIPTION AND OPERATION (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, clutch, or high operating
pressure. Verify compressor drive belt condition,
proper refrigerant charge and head pressure before
compressor repair is performed.
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.
Fig. 7 A/C PERFORMANCE TEMPERATURES
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
24 - 12 HEATING AND AIR CONDITIONINGNS/GS
DIAGNOSIS AND TESTING (Continued)