WIPER CHRYSLER VOYAGER 1996 Owners Manual

to support the hood, install bottom bolts to hold hood
to hinge finger tight.
(2) Install top bolts to hold hood to hinge finger
tight.
(3) Position bolts at marks and tighten bolts. The
hood should be aligned to 4 mm (0.160 in.) gap to the
front fenders and flush across the top surfaces along
fenders.
(4) Verify hood operation and alignment.
HOOD HINGE
REMOVAL
(1) Remove hood.
(2) Remove wiper unit. Refer to Group 8K, Wind-
shield Wipers and Washers, for procedure.
(3) Mark all bolt and hinge attachment locations
with a grease pencil or other suitable device to pro-
vide reference marks for installation.
(4) Remove bolts attaching body half of hood hinge
to front fender flange and remove hinge from vehicle
(Fig. 45).
INSTALLATION
(1) If necessary, paint new hinge before installa-
tion.
(2) Place body half of hood hinge in position on
vehicle.
(3) Install bolts to hold hood hinge to front fender
flange.
(4) Install wiper unit. Refer to Group 8K, Wind-
shield Wipers and Washers, for proper procedures.
(5) Install hood.
(6) Align all marks and secure bolts. The hood
should be aligned to 4 mm (0.160 in.) gap to the front
fenders and flush across the top surfaces along fend-
ers. Shims can be added or removed under hood
hinge to achieve proper hood height.
HOOD LATCH
REMOVAL
(1) Release hood latch and open hood.
(2) Remove bolts holding hood latch to radiator clo-
sure panel crossmember (Fig. 46).
(3) Remove hood latch from crossmember.
(4) Disconnect hood release cable from hood latch
(Fig. 47).
(5) Remove hood latch from vehicle.
INSTALLATION
(1) Position hood latch on vehicle.
(2) Connect hood release cable from hood latch.
(3) Position hood latch on crossmember.
(4) Align hood latch by placing latch over net-
pierced tabs. If alignment is required, flatten tabs.
(5) Install bolts attaching hood latch to radiator
closure panel crossmember.
(6) Verify hood operation and alignment. Adjust as
necessary.
Fig. 44 HoodFig. 45 Hood Hinge
Fig. 46 Hood Latch
NSBODY 23 - 41
REMOVAL AND INSTALLATION (Continued)

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. 3).
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
and washer operation, front & rear window defogger,
recirculation door operation, and A/C compressor
operation if equipped. Refer to Group 8E, Instrument
Panel and Systems for service procedures.
NOTE: The RECIRC. function on the HVAC control
module automatically defaults to the OFF position
after a ignition key cycle. To reactivate the RECIRC.
function, the RECIRC. button must be repressedThe rear blower speed switch is serviced separately
from the control head.
SIDE DOOR HEATER A/C OUTLETS
The driver's and passenger side doors have supple-
mental air outlets and duct work. The air is chan-
neled from the instrument panel to the door duct and
either to the lower floor or upper door outlets (Fig.
4). The air can be adjusted to blow on the first rear
passenger seat(s).
SIDE WINDOW DEMISTER
The side window demisters direct air from the
heater assembly. The outlets are located on the top
forward corners of the front door panels (Fig. 5). The
demisters operate when the control mode selector is
on FLOOR, MIX or DEFROST setting.
SYSTEM AIRFLOW
The system pulls outside (ambient) air through the
cowl opening at the base of the windshield. Then it
goes into the plenum chamber above the heaterÐA/C
Fig. 3 HVAC Control Module
Fig. 4 Door Outlets
24 - 4 HEATING AND AIR CONDITIONINGNS
DESCRIPTION AND OPERATION (Continued)

DIAGNOSTICS
During the Actuator calibration, diagnostics are
performed on the actuators and evaporator tempera-
ture Fin Sensor. Once diagnostics are completed the
REAR WIPER and INTERMITTENT LED's will flash
to indicate either a successful calibration or the
appropriate fail code(s). At this time manual testing
of the Blend, Mode and Driver (if equipped) potenti-
ometers can be performed. If a failure is detected
during Diagnostics a fault will be set in the control.
When Ignition is cycled OFF and then ON or Diag-
nostics is aborted, the REAR WIPER and INTER-
MITTENT LED's will flash simultaneously showing
that a failure has occurred. The control will not indi-
cate the fail code, but only that a failure had
occurred during the last diagnostics test. The only
way to clear the failure codes is repeat the Calibra-
tion Diagnostic and Cooldown test, after all repairs
are completed.
COOLDOWN TEST
This test has been designed for performance test-
ing of the A/C system at the manufacturing facility. If
the HVAC control module is replaced, the Cooldown
test will occur during Calibration test. Cooldown will
not occur on Heater Only units. During the Cooldown
test the control will monitor the temperature of the
Fin Sensor. The A/C system must be able to bring the
evaporator temperature down a predetermined mini-
mum amount in less than 2 minutes.
CALIBRATION/COOLDOWN LED DISPLAY
CODES
See table for definition of flashing LED's. If no
problems are found, the control functions normally.
CALIBRATION/DIAGNOSTICS TEST ENTRY
TO INITIATE TESTS:
²Set Blower motor ON HIGH
²Set Mode position to Panel
²Open all A/C outlets
²Set Temperature to Cold (Both slide pots if
equipped)
²Depress WASH and REAR WIPER button simul-
taneously for 5 Seconds (Until all LED's light)
RESULTS:
²All LED's will turn on for 5 Seconds
²Calibration Test is running when REAR WIPER
and INTERMITTENT are alternately flashing.
Cooldown test is running if A/C and RECIRC are
alternately flashing.
²Acceptable results is REAR WIPER LED is the
only LED flashing. Push Rear Wiper to exit.
²After all tests have passed, Calibration Diagnos-
tics and Cooldown can be run separately.
Fig. 7 Radio Bezel and HVAC Control, Rear Blower
Motor Switch and Zone Control
CALIBRATION/COOLDOWN LED DISPLAY
CODES
LED'S PASS/FAILCORREC-
TIVE
ACTION
NO LED'S
FLASHING-
NORMAL
OPERATIONPASSED
CALIBRATION,
DIAGNOSTICS
AND
COOLDOWNNONE
REAR WIPER AND
INTERMITTENT
LED'S FLASH
SIMULTANEOUSLYFAILED
CALIBRATION
DIAGNOSTICSRUN
CALIBRATION
TEST
A/C AND RECIRC
LED'S FLASH
SIMULTANEOUSLYFAILED
COOLDOWNRUN
COOLDOWN
TEST
REAR WIPER AND
INTERMITTENT
LED'S ARE
FLASHING
SIMULTANEOUSLY
A/C AND RECIRC
LED'S ARE
FLASHING
SIMULTANEOUSLYFAILED
CALIBRATION,
DIAGNOSTICS
AND FAILED
COOLDOWN
TESTRUN
CALIBRATION
TEST
NSHEATING AND AIR CONDITIONING 24 - 7
DIAGNOSIS AND TESTING (Continued)

COOLDOWN TEST ENTRY
TO INITIATE TESTS:
²Set Blower motor ON HIGH
²Set Mode position to Panel
²Open all A/C outlets
²Set Temperature to Cold (Both slide pots if
equipped)
²Depress WASH and A/C simultaneously for 5
Seconds
NOTE: Prior to start of test, If the evaporator is
already cold, the system will fail test. To correct,
operate system with A/C OFF and the blower motor
ON high for three minutes prior to starting test.
RESULTS:
²All LED's will turn on for 5 Seconds
²Cooldown Test is running when A/C and
RECIRC. are alternately flashing. If A/C and
RECIRC. are flashing simultaneously, Cooldown has
failed.
CALIBRATION DIAGNOSTICS AND
COOLDOWN ABORT
Test can be aborted by doing one of the following:
²Depressing Rear Window Defogger, RECIRC and
Rear Wiper buttons.
²Cycling Ignition OFF and then ON.
²Control will automatically abort after 15 min-
utes from the time Calibration Diagnostics and
Cooldown was entered.
The HVAC control module will return to normal
operation or may indicate unsuccessful Calibration
Diagnostics or Cooldown test by LED's flashing
simultaneously.
EEPROM DATA
Calibration Diagnostics, Cooldown Status and
evaporator temperature Fin Sensor values are stored
in an EEPROM memory internal to the control. The
microcomputer within the HVAC control module uses
this information:
²To determine if Cooldown needs to run
²For proper position of the Heater-A/C unit
assembly doors
ACTUATOR CALIBRATION AND
DIAGNOSTICS.
NOTE: Do not run actuators unless they are prop-
erly mounted on the HVAC control module.
Actuator end point calibration takes approximately
60 seconds. The REAR WIPER and INTERMITTENT
LED's will flash alternately during the test. The con-
trol will cycle the Blend actuator(s) to the Heat stopfirst then back to Cold. After the Blend actuator(s)
have been calibrated the Mode actuator will be cycled
to Defrost and then to Panel. Successful calibration
is defined as actuator travel falling within their min-
imum and maximum limits.
BLEND/PASSENGER ACTUATOR BACKGROUND
The Blend/Passenger Actuator can move the tem-
perature door in two directions. When the voltage at
Pin 12 of the control module is high, about 11.5 volts,
and the voltage at Pin 17 is low, about 1.5 volts, the
door will move towards the Heat position. When Pin
17 is High and Pin 12 is Low the door will move
towards the Cold position. When both Pins are high
or both Pins are low, the actuator will not move. The
Blend/Passenger feedback signal is a voltage signal
that is supplied by the actuator to the control. The
signal will be about 4.0 volts in the Heat position
and 1.0 volt in the Cold position. As the position of
the Blend/Passenger actuator changes, so will the
feedback signal. The feedback signal is necessary for
the correct positioning of the temperature door.
DRIVER ACTUATOR BACKGROUND
The Driver Actuator can move the temperature
door in two directions. When the voltage at Pin 15 of
the control module is high, about 11.5 volts, and the
voltage at Pin 13 is low, about 1.5 volts the door will
move towards the Cold position. When Pin 13 is High
and Pin 15 is Low the door will move towards the
Heat position. When both Pins are high or when both
Pins are low, the actuator will not move. The Driver
feedback signal is a voltage signal that is supplied by
the actuator to the control. The signal will be about
4.0 volts in the Heat position and 1.0 volt in the Cold
position. As the position of the Driver Actuator
changes, so will the feedback signal. The feedback
signal is necessary for the correct positioning of the
temperature door.
MODE ACTUATOR BACKGROUND
The Mode actuator can move the mode door in two
directions. When the voltage at Pin 18 of the control
module is high, about 11.5 volts, and the voltage at
Pin 12 is low, about 1.5 volts the door will move
towards the Panel position. When Pin 12 is High and
Pin 18 is Low the door will move towards the Defrost
position. When both Pin are high or when both Pins
are low, the actuator will not move. The Mode door
feedback signal is a voltage signal that is supplied by
the actuator to the control. The signal will be about
4.5 volts in the Panel position and 0.5 volts in the
Defrost position. As the position of the Mode actuator
changes, so will the feedback signal. The feedback
signal is necessary for the correct positioning of the
mode door.
24 - 8 HEATING AND AIR CONDITIONINGNS
DIAGNOSIS AND TESTING (Continued)

FAIL CODES/LEVEL DISPLAY
Fail Codes/Level are displayed using the REAR
WIPER and INTERMITTENT LED's flashing in the
sequence indicated below. The REAR WIPER LED
represents the Level and the INTERMITTENT LED
represents the Value. After Calibration/Diagnostics is
completed, the control will begin flashing Level 1
codes. Depressing the WASH button will cycle to
Level 2, depressing WASH again will cycle to Level 3.
Each time the WASH button is depressed will cycle
to the next level. After Level 5 is reached, you will
cycle back to Level 1. If the Control is a Heater Only
you will only cycle from Levels 1 to 3.
TEMPERATURE AND MODE POTENTIOMETER
DIAGNOSTICS
The Temperature and Mode Potentiometer can be
tested after calibration is complete by pressing the
WASH button and cycling to Levels 2, 3 or 5 as dis-
played by the REAR WIPER LED. On Heater Only
units you can only cycle to Levels 2 and 3. In eachindividual test the INTERMITTENT LED flash rate
will change as the Temperature or Mode potentiome-
ter is moved from one end to the other, see Potenti-
ometer vs. Position and Flash Rate table.
EVAPORATOR PROBE TEMPERATURE
DIAGNOSTICS
The evaporator probe can be tested by using the
INTERMITTENT LED to display the actual temper-
ature the sensor is reading. The HVAC control mod-
ule can only display temperatures from 1 to 99
degrees. To read the temperature, perform the follow-
ing:
²Set Blower motor to any speed other than OFF
²Set A/C to ON, if A/C Clutch does not engage
make sure Fail Codes 5 and 6 are cleared.To clear
the error code 5 and 6 the evaporator probe and/or
the wiring repair needs to be completed. Then, press
and hold the intermittent wipe button for 5 seconds.
²Run Diagnostics (Depress REAR WIPER and
REAR WASH)
²When Diagnostics is complete, Cycle to Level 4.
Display Sequence is as follows:
²REAR WIPER LED will display the Level
²INTERMITTENT LED will display ten's digit
²Short Pause
²INTERMITTENT LED will display the one's
digit.
The HVAC control module will continue to cycle
the Level and then Temperature until the level is
changed or Calibration Diagnostics and Cooldown
test is exited.
HVAC CONTROL DIAGNOSTIC CONDITIONS
For wiring circuits, wiring connectors, and Pin
numbers, refer to Group 8W, Wiring Diagrams.
After calibration, Rear Wiper LED flashing
once, Intermittent LED not flashing.
The system has passed calibration. Press the Rear
Wiper button to exit calibration.
WIPE BUTTON LED
LEVEL DISPLAY
1 FAIL CODES
2 MODE POTENTIOMETER TEST
3 BLEND/PASS. POTENTIOMETER TEST
4 EVAPORATOR PROBE (A/C AND ZONE
UNITS ONLY)
5 DRIVER POTENTIOMETER (ZONE UNITS
ONLY)
LEVEL 1±FAILURE CODE VALUES
(INTERMITTENT WIPE BUTTON LED)
CODE DEFINITION
0 PASSED ALL TESTS
1 MODE ACTUATOR DID NOT REACH
DEFROST POSITION
2 MODE ACTUATOR DID NOT REACH
PANEL POSITION
3 BLEND/PASS. ACTUATOR DID NOT
REACH COLD STOP
4 BLEND PASS. ACTUATOR DID NOT
REACH HEAT STOP
5 EVAPORATOR PROBE OPEN
6 EVAPORATOR PROBE SHORTED
7 DRIVER ACTUATOR DID NOT REACH
COLD STOP
8 ZONE/DRIVER ACTUATOR DID NOT
REACH HEAT STOP
9 CONTROL HEAD INTERNAL FAILURE
POTENTIOMETER VS. POSITION AND FLASH
RATE
POTENTIOM-
ETERINTERMIT-
TENT LED
FASTER
FLASH RATEINTERMITTENT
LED SLOWER
FLASH RATE
MODE PANEL DEFROST
BLEND/PASS. HOT COLD
DRIVER HOT COLD
NSHEATING AND AIR CONDITIONING 24 - 9
DIAGNOSIS AND TESTING (Continued)

After calibration, Rear Wiper LED flashing
once, Intermittent LED flashing once. The
mode actuator did not reach defrost position.
(1) Using a voltmeter, check the mode door actua-
tor wiring connector. Check Pin 1 for battery voltage.
Move the HVAC control from the defrost to panel
position, and check Pin 6 voltage it should change
from 0.5 - 1 volts to 3.5 - 4.5 volts. If voltage is OK,
go to Step 2. If not OK, check for loose or corroded
connector, open or shorted circuit and repair as nec-
essary.
(2) Remove actuator, and check if the gear pins are
in the correct track on cam or if they are binding. If
OK, go to Step 3. If not OK, repair as necessary.
(3) Check for binding door, if door is binding repair
as necessary. If gears and door are OK, replace
actuator.
(4) Once repairs are completed repeat the Calibra-
tion Diagnostic and Cooldown test. Repeating the
test is necessary to clear the fault codes.
After calibration, Rear Wiper LED flashing
once, Intermittent LED flashing twice. The
mode actuator did not reach panel position.
(1) Using a voltmeter, check the mode door actua-
tor wiring connector. Check Pin 1 for battery voltage.
Move the HVAC control from panel to defrost posi-
tion, and check Pin 6 voltage it should change from
3.5 - 4.5 volts to 0.5 - 1 volts. If voltage is OK, go to
Step 2. If not OK, check for loose or corroded connec-
tor, open or shorted circuit and repair as necessary.
(2) Remove actuator, and check if the gear pins are
in the correct cam track or binding. If OK, go to Step
3. If not OK, repair as necessary.
(3) Check for binding door, if door is binding repair
as necessary. If gears and door are OK, replace
actuator.
(4) Once repairs are completed repeat the Calibra-
tion Diagnostic and Cooldown test. Repeating the
test is necessary to clear the fault codes.
After calibration, Rear Wiper LED flashing
once, Intermittent LED flashing three times.
The main temperature actuator/passenger
temperature actuator on a zone system did
not reach cold stop.
(1) Check if the correct HVAC control module was
used.
(2) Using a voltmeter, check the temperature door
actuator wiring connector. Check Pin 1 for battery
voltage. Move the HVAC control from the cold to hot
position, and check Pin 5 voltage it should change
from 0.5 - 4 volts to 3.5 - 4.5 volts. If voltage is OK,
go to Step 3. If not OK, check for loose or corroded
connector, open or shorted circuit and repair as nec-
essary.(3) Remove actuator, and check if gear pins are in
the correct cam track or binding. If OK, go to Step 4.
If not OK, repair as necessary.
(4) Check for binding door, if door is binding repair
as necessary. If gears and door are OK, replace
actuator.
(5) Once repairs are completed repeat the Calibra-
tion Diagnostic and Cooldown test. Repeating the
test is necessary to clear the fault codes.
After calibration, Rear Wiper LED flashing
once, Intermittent LED flashing four times.
The main temperature actuator/passenger
temperature actuator on a zone system did
not reach hot stop.
(1) Check if the correct HVAC control module was
used.
(2) Using a voltmeter, check the temperature door
actuator wiring connector. Check Pin 1 for battery
voltage. Move the HVAC control from hot to cold
position and check Pin 5 voltage it should change
from 3.5 -4.5 volts 0.5 - 1.5 volts. If voltage is OK, go
to Step 3. If not OK, check for loose or corroded con-
nector, open or shorted circuit and repair as neces-
sary.
(3) Remove actuator, and check if the gear pins are
in the correct track on cam or if they are binding. If
OK, go to Step 4. If not OK, repair as necessary.
(4) Check for binding door, if door is binding repair
as necessary. If gears and door are OK, replace
actuator.
(5) Once repairs are completed repeat the Calibra-
tion Diagnostic and Cooldown test. Repeating the
test is necessary to clear the fault codes.
After calibration, Rear Wiper LED flashing
once, Intermittent LED flashing five times.
The evaporator probe is open.
(1) Using a voltmeter, check Pin 1 of the evapora-
tor probe wiring connector for 0.1 - 4.75 volts. If OK,
go to Step 2. If not OK, if greater than 4.75 volts
check for loose or corroded connector, open circuit
and repair as necessary.
(2) Using a ohmmeter, check Pin 2 for a good
ground, If OK, go to Step 3. If not OK, check for loose
or corroded connector, open or shorted circuit and
repair as necessary.
(3) If ground and power circuit are OK, replace
Evaporator Probe.
(4) Once repairs are completed, press the intermit-
tent button about 5 seconds until all LED's light to
remove fault code from memory. Then repeat the Cal-
ibration Diagnostic and Cooldown test. Repeating the
test is necessary to clear the fault codes.
24 - 10 HEATING AND AIR CONDITIONINGNS
DIAGNOSIS AND TESTING (Continued)

After calibration, Rear Wiper LED flashing
once, Intermittent LED flashing six times. The
evaporator probe is shorted.
(1) Using a voltmeter, check Pin 1 of the evapora-
tor probe wiring connector for 0.1 - 4.75 volts. If OK,
go to Step 2. If less than 0.1 volts, check for loose or
corroded connector, open or shorted circuit and repair
as necessary.
(2) Using a ohmmeter, check Pin 2 for a good
ground, If OK, go to Step 3. If not OK, check for
shorted circuit and repair as necessary.
(3) If ground and power circuit are OK, replace
Evaporator Probe
(4) Once repairs are completed, press the intermit-
tent button about 5 seconds until all LED's light to
remove fault code from memory. Then repeat the Cal-
ibration Diagnostic and Cooldown test. Repeating the
test is necessary to clear the fault codes.
After calibration, Rear Wiper LED flashing
once, Intermittent LED flashing seven times.
The Driver's temperature actuator on a zone
system did not reach cold stop.
(1) Check if the correct HVAC control module was
used.
(2) Using a voltmeter, check at the temperature
door actuator wiring connector, check Pin 1 for bat-
tery voltage. Move the HVAC control from cold to the
hot position, check Pin 4 voltage it should change
from 0.5 - 1.5 volts 3.5 - 4.5 volts. If voltage is OK, go
to Step 3. If not OK, check for loose or corroded con-
nector, open or shorted circuit and repair as neces-
sary.
(3) Remove actuator, and check if the gear pins are
in the correct track on cam or if they are binding. If
OK, go to Step 4. If not OK, repair as necessary.
(4) Check for binding doors, if door are binding
repair as necessary. If gears and door are OK, replace
actuator.
(5) Once repairs are completed repeat the Calibra-
tion Diagnostic and Cooldown test. Repeating the
test is necessary to clear the fault codes.
After calibration, Rear Wiper LED flashing
once, Intermittent LED flashing eight times.
The Driver's temperature actuator on a zone
system did not reach hot stop.
(1) Check if the correct HVAC control module was
used.
(2) Using a voltmeter, check at the temperature
door actuator wiring connector, check Pin 1 for bat-
tery voltage. Move the HVAC control from hot to cold
position, Pin 4 voltage it should change from 3.5 - 4.5
volts to 0.5 - 1.5 volts. If voltage is OK, go to Step 3.
If not OK, check for loose or corroded connector, open
or shorted circuit and repair as necessary.(3) Remove actuator, and check if the gear pins are
in the correct track on cam or if they are binding. If
OK, go to Step 4. If not OK, repair as necessary.
(4) Check for binding door, if door is binding repair
as necessary. If gears and door are OK, replace
actuator.
(5) Once repairs are completed repeat the Calibra-
tion Diagnostic and Cooldown test. Repeating the
test is necessary to clear the fault codes.
After calibration, Rear Wiper LED flashing
once, Intermittent LED flashing nine times.
The HVAC control module, has a internal
failure.
(1) Replace the HVAC control module.
(2) Once repairs are completed repeat the Calibra-
tion Diagnostic and Cooldown test. Repeating the
test is necessary to clear the fault codes.
After calibration and testing the A/C and
RECIRC LED flashing simultaneously. Failed
Cooldown test.
(1) Determine if the refrigerant system is operat-
ing correctly:
²Check the outlet air temperature
²Feel the compressor suction plumbing, is it hot?
(2) If not OK, go to Step 3. If OK, repeat the Cal-
ibration Diagnostic and Cooldown test.
(3) If system does not seem to be operating cor-
rectly, perform diagnostics for poor performance:
²Low refrigerant charge
²No charge
²Compressor not operating
Verify that the test was done with the evaporator
at room temperature. The test consists of starting
the compressor and measuring the time it takes for
the evaporator temperature to fall 7ÉC (20ÉF). If the
compressor has been running, the evaporator is cold
already and will not be capable of falling 7ÉC (20ÉF).
If the test was run with a cold evaporator, turn A/C
off and turn the blower motor switch to high position
for 3 to 5 minutes till the evaporator is to room tem-
perature. Then repeat the Calibration Diagnostic and
Cooldown test.
If refrigerant system is performing properly and
the system will not pass test. Repeat the Calibration
Diagnostic and Cooldown test to determine if the
evaporator temperature FIN sensor has developed an
open or a short circuit. If the HVAC control module
still passes Calibration test, verify Cooldown test
manually with a pocket thermometer. The outlet air
temperature must drop at least 7ÉC (20ÉF) within
two minutes. If the vehicle passes with the manual
thermometer, take HVAC control to level 4 (evapora-
tor probe temperature readout) and repeat the
Cooldown test. Ensure the evaporator is at room tem-
perature before starting test. Check if evaporator
NSHEATING AND AIR CONDITIONING 24 - 11
DIAGNOSIS AND TESTING (Continued)

(3) Locate and remove the wire connector from the
blower resistor block. Block is located at the back of
the engine compartment on the passenger side of the
vehicle under the wiper module (Fig. 19).
NOTE: It may not necessary to remove the wiper
module to access the resistor block.
(4) Using a long flad blade screwdriver, gently
push in on drivers side of resistor. Be careful to catch
the inner release tang and gently pry outward (Fig.
20).
WARNING: THE RESISTOR BLOCK MAY BE HOT.
DO NOT ATTEMPT TO SERVICE THE RESISTOR
BLOCK IF THE SYSTEM HAS BEEN RUNNING
RECENTLY. LET THE SYSTEM COOL DOWN
BEFORE REPAIRS ARE INITIATED.
(5) Remove resistor block by inserting a flat blade
pry tool on the side of the resistor block and pushing
inward. Two guide lines are shown on the right hand
edge of the resistor block to help guide the bladeposition. This will release the clips on the side of the
resistor block. Pull resistor block out.
INSTALLATION
For installation, reverse the above procedures.
Make sure the ªTOPº lettering is on the top of the
resistor. The coils on the Resistor Block should not be
contacting one another. Before installation, gently
separate the coils (with fingers only) if one coil is
contacting another.
BLOWER MOTOR WHEEL
The blower motor wheel is not serviced separately.
If the wheel needs to be replaced it is serviced as an
assembly of the blower motor. For service procedure
information, refer to Blower Motor Replacement in
this group.
Fig. 18 Blower Motor Screws
Fig. 19 Resistor Block Location
Fig. 20 Resistor Block Removal
24 - 22 HEATING AND AIR CONDITIONINGNS
REMOVAL AND INSTALLATION (Continued)

(2) Remove liquid line at filter-drier (Fig. 42).
(3) Remove the (2) bolts holding filter-drier bracket
to radiator fan module bracket.
(4) Remove the lower liquid line at condenser.
(5) Remove the upper radiator crossmember.
(6) Pull up on radiator and slide filter-drier from
the mounting location.
INSTALLATION
(1) Before installation, replace both refrigerant
line O-rings. Then reverse the above procedures.
Torque filter/drier mounting bolts to 45 in. lbs.610.
(2) Evacuate and recharge system.
HEATER A/C UNIT HOUSING
REMOVAL
WARNING: IF EQUIPPED WITH AIR CONDITIONING,
THE REFRIGERATION SYSTEM MUST BE COM-
PLETELY EMPTY BEFORE PROCEEDING.
(1) Set parking brake.
(2) Disconnect battery negative cable.
(3) Using a refrigerant recovery machine, remove
refrigerant from the A/C system (Fig. 43).
(4) Remove wiper module. Refer to Group 8K,
Windshield Wipers and Washers.
(5) Pinch off rear heater lines if equipped.
(6) Drain engine coolant. Remove heater hoses at
the heater core (Fig. 44). Plug coolant lines.
(7) Remove suction and liquid lines at the expan-
sion valve (Fig. 45).(8) Remove the Instrument Panel Assembly. Refer
to Group 8E, Instrument Panel and Gauges.
(9) Remove heater ducts.
Fig. 42 Filter-Drier Assembly
Fig. 43 A/C Service Ports
Fig. 44 Heater Hoses
Fig. 45 Expansion Valve Plate
NSHEATING AND AIR CONDITIONING 24 - 29
REMOVAL AND INSTALLATION (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)