1996 CHRYSLER VOYAGER oil temperature

CAUTION: Some clutch packs appear similar, but
they are not the same. Do not interchange clutch
components, as they might fail.
HYDRAULICS
The hydraulics of the transaxle provide:
²Manual shift lever select function
²Main line pressure regulation
²Torque converter and cooler flow control
Oil flow to the friction elements is controlled
directly by four solenoid valves. The hydraulics also
include a unique logic- controlled solenoid torque con-
verter clutch control valve. This valve locks out the
1st gear reaction element with the application of 2nd,
direct, or overdrive gear elements. It also redirects
the 1st gear solenoid output so that it can control
torque converter clutch operation. To regain access to
1st gear, a sequence of commands must be used to
move the solenoid TCC control valve. This precludes
any application of the 1st gear reaction element with
other elements applied. It also allows one solenoid to
control two friction elements.
Small, high-rate accumulators are provided in each
controlled friction element circuit. These serve to
absorb the pressure responses, and allow the controls
to read and respond to changes that are occurring.
SOLENOIDS
The solenoid valves perform most control functions,
these valves must be extremely durable and tolerant
of dirt. For that reason hardened-steel poppet and
ball valves are used. These are free from any close
operating clearances. The solenoids operate the
valves directly without any intermediate element.
Direct operation means that these units must have
very high output. They must close against the size-
able flow areas and high line pressures. Fast
response is also required to meet the control require-
ments.
Two of the solenoids are normally-venting and two
are normally-applying; this was done to provide a
default mode of operation. With no electrical power,
the transmission provides 2nd gear in (OD), (3), or
(L) shift lever positions. All other transmission lever
positions will operate normally. The choice of 2nd
gear was made to provide adequate breakaway per-
formance while still accommodating highway speeds.
SENSORS
There are three pressure switches to identify sole-
noid application. There are two speed sensors to read
input (torque converter turbine) and output (parking
sprag) speeds. There is also a transmission range
sensor to indicate the manual shift lever position.
The pressure switches are incorporated in an assem-
bly with the solenoids. Engine speed, throttle posi-tion, temperature, etc., are also observed. Some of
these signals are read directly from the engine con-
trol sensors; others are read from a multiplex circuit
with the powertrain control module.
ELECTRONICS
The 41TE Transmission Control Module (TCM) is
located underhood in a potted, die-cast aluminum
housing. The module used is a new controller called
EATX III. The TCM has a sealed, 60-way connector.
ADAPTIVE CONTROLS
These controls function by reading the input and
output speeds over 140 times a second and respond-
ing to each new reading. This provides the precise
and sophisticated friction element control needed to
make smooth clutch-to-clutch shifts for all gear
changes. The use of overrunning clutches or other
shift quality aids are not required. As with most
automatic transaxles, all shifts involve releasing one
element and applying a different element. In simpli-
fied terms, the upshift logic allows the releasing ele-
ment to slip backwards slightly. This ensures that it
does not have excess capacity. The apply element is
filled until it begins to make the speed change to the
higher gear. The apply pressure is then controlled to
maintain the desired rate of speed change. This con-
tinues until the shift is made. The key to providing
excellent shift quality is precision. For example, the
release element for upshifts is allowed to slip back-
wards slightly. The amount of that slip is typically
less than a total of 20 degrees. To achieve that pre-
cision, the TCM learns the traits of the transaxle
that it is controlling. It learns the release rate of the
releasing element and the apply time of the applying
element. It also learns the rate at which the apply
element builds pressure sufficient to begin making
the speed change. This method achieves more preci-
sion than would be possible with exacting tolerances.
It can also adapt to any changes that occur with age
or environment.
For kickdown shifts, the control logic allows the
releasing element to slip. Then controls the rate at
which the input (and engine) accelerate. When the
lower gear speed is achieved, the releasing element
reapplies to maintain that speed until the apply ele-
ment is filled. This provides quick response since the
engine begins to accelerate immediately. This also
provides a smooth torque exchange since the release
element can control the rate of torque increase. This
control can make any powertrain feel more respon-
sive without increasing harshness.
Adaptive controls respond to input speed changes.
They compensate for changes in engine or friction
element torque and provide good, consistent shift
quality for the life of the transaxle.
NSTRANSAXLE AND POWER TRANSFER UNIT 21 - 73
DESCRIPTION AND OPERATION (Continued)

If a problem arises with the shifter position indica-
tor, consult the following chart for diagnostic infor-
mation. If the malfunction cannot be corrected using
the chart, consult the proper diagnostic manual.
To replace the shifter position indicator, refer to
Group 8E, Instrument Panel And Gauges.SERVICE PROCEDURES
FLUID AND FILTER CHANGE
When the factory fill fluid is changed, only fluids
labeled MOPARtATF PLUS 3 (Automatic Transmis-
sion fluid) Type 7176 should be used.
If the transaxle is disassembled for any reason, the
fluid and filter should be changed.
30,000 MILE TRANSAXLE OIL CHANGE
When a vehicle attains 30,000 miles on its odome-
ter it is recommended that the transaxle oil be
changed. To change the oil, use the procedure that
follows:
It is recommended that a transaxle fluid exchanger
(ATF 2000+ or equivalent) be used to replace the
used fluid in the transaxle. If a fluid exchanger is not
available use a fluid suction pump (Vaculayor equiv-
alent) to draw the fluid out of the dipstick tube. If a
fluid suction pump is not available remove the oil
pan and drain the fluid.
CAUTION: Chrysler Corporation does not recom-
mend using any fluid exchanger that introduces
additives into the transaxle.
TRANSAXLE FLUID EXCHANGER METHOD
(1) To perform the transaxle fluid exchange, the
transaxle must be at operating temperature. Drive
the vehicle till it reaches full operating temperature.
(2) Verify that the fill tank on the transaxle fluid
exchanger (ATF 2000+ or equivalent) is clean and
dry.
(3) Fill the tank to the recommended fill capacity
with Mopar ATF Plus 3 Type 7176.
(4) Hookup the vehicle to the machine following
the manufacturers instructions. Perform the
exchange procedure following the instructions pro-
vided with the machine.
(5) Once machine has completed the fluid
exchange. Check the fluid level and condition and fill
to proper level with Mopar ATF Plus 3 Type 7176.
NOTE: Verify that the transaxle cooler lines are
tightened to proper specifications. Cooler line
torque specification is 2 N´m (18 in. lbs.).
CONDITION POSSIBLE CAUSE
ALL PRND3L DISPLAY
LIGHTS9ON9IN P&N
GEAR POSITIONS1.Check wiring and
connectors
2. Faulty trans. range
sensor
3. Faulty manual lever
ALL DISPLAY LIGHTS
9ON9IN ALL GEAR
POSITIONS1. Check wiring &
connectors
2. Faulty trans. range
sensor
3. Faulty manual lever
4. CCD communication
malfunction
5. Check oil level
ALL DISPLAY LIGHTS
9OFF91. Normal transient
condition between P&R
and R&N gear positions
2. Check shift lever
linkage
3. Body controller
malfunction
4. Check wiring and
connectors
5. Faulty cluster
ALL DISPLAY LIGHTS
9OFF9ACCOMPANIED
BY A9NO BUS9
MESSAGE1. CCD communication
malfunction
DISPLAY LIGHTS OUT
OF SEQUENCE WITH
SHIFT LEVER1. Check wiring and
connectors
2. Faulty trans. range
sensor
3. Faulty manual lever
4. CCD communication
malfunction
NSTRANSAXLE AND POWER TRANSFER UNIT 21 - 79
DIAGNOSIS AND TESTING (Continued)

DIPSTICK TUBE FLUID SUCTION METHOD
(1) When performing the fluid suction method,
make sure the transaxle is at full operating temper-
ature.
(2) To perform the dipstick tube fluid suction
method, use a suitable fluid suction device (Vaculay
or equivalent).
(3) Insert the fluid suction line into the dipstick
tube.
NOTE: Verify that the suction line is inserted to the
lowest point of the transaxle oil pan. This will
ensure complete evacuation of the fluid in the pan.
(4) Follow the manufacturers recommended proce-
dure and evacuate the fluid from the transaxle.
(5) Remove the suction line from the dipstick tube.
(6) Add 4 Quarts of Mopar ATF Plus 3 Type 7176
transaxle fluid.
(7) Start the engine and allow it to idle for a min-
imum of one minute. With the parking brake applied,
press your foot on the service brake and cycle the
transaxle from park to all gear positions ending in
neutral or park.
(8) Check the transaxle fluid level and add an
appropriate amount to bring the transaxle fluid level
to 3mm (1/8 in.) below the ADD mark on the dip-
stick.
(9) Recheck the fluid level after the transaxle is at
normal operating temperature. The level should be in
the HOT range.
TRANSAXLE OIL PAN DROP METHOD
This procedure involves removing the transaxle oil
pan to drain the transaxle fluid.
(1) Bring the vehicle up to normal operating tem-
perature. Drive the vehicle a minimum of 10 miles.
(2) Raise the vehicle on the hoist.
(3) Loosen the transaxle oil pan and drain the
fluid into a suitable container.
(4) Remove the pan and clean all sealant from the
pan and transaxle mating surfaces. Clean the mag-
net and the inside of the pan.
(5) Apply a 1/8 inch bead of Mopar RTV Sealant to
the mounting flange of the transaxle oil pan. Apply
RTV Sealant to the underside of the attaching bolts.
Attach the oil pan to the transaxle. Tighten the bolts
to 19 N²m (165 in. lbs.).
(6) Lower the vehicle and add 4 Quarts of Mopar
ATF Plus 3 Type 7176 transaxle fluid.
(7) Start the engine and allow it to idle for a min-
imum of one minute. With the parking brake applied,
press your foot on the service brake and cycle the
transaxle from park to all gear positions ending in
neutral or park.
(8) Check the transaxle fluid level and add an
appropriate amount to bring the transaxle fluid levelto 3mm (1/8 in.) below the ADD mark on the dip-
stick.
(9) Recheck the fluid level after the transaxle is at
normal operating temperature. The level should be in
the HOT range. Drive the vehicle a minimum of 10
miles.
(10) Raise the vehicle on the hoist.
(11) Check for leaks around the transaxle oil pan
sealing surfaces.
(12) Recheck the fluid level. The level should be in
the HOT range.
SEVERE USAGE SERVICE
If the vehicle exhibits any of the following symp-
toms, it is recommended that the transaxle oil and
filter be replaced.
²Transaxle oil discolored
²Transaxle oil has high mileage
²Oil feels grimy when rubbed between fingertips
²Poor shift quality
²Delayed gear engagement
²Vehicle shudder between shifts
TRANSAXLE OIL AND FILTER REPLACEMENT
This procedure involves changing the transaxle
fluid and filter, driving the vehicle for 10 miles and
changing the transaxle fluid a second time.
(1) Bring the vehicle up to normal operating tem-
perature. Drive the vehicle a minimum of 10 miles.
(2) Raise the vehicle on the hoist.
(3) Loosen the transaxle oil pan and drain the
fluid into a suitable container.
(4) Remove the pan and clean all sealant from the
pan and transaxle mating surfaces. Clean the mag-
net and the inside of the pan.
(5) Separate the filter and O-ring from the valve
body. Inspect the O-ring for cuts or improper instal-
lation. This could lead to delayed garage shifts.
(6) Install a new filter. Replace the O-ring as nec-
essary.
(7) Apply a 1/8 inch bead of Mopar RTV Sealant to
the mounting flange of the transaxle oil pan. Apply
RTV Sealant to the underside of the attaching bolts.
Attach the oil pan to the transaxle. Tighten the bolts
to 19 N´m (165 in. lbs.).
(8) Lower the vehicle and add 4 Quarts of Mopar
ATF Plus 3 Type 7176 transaxle fluid.
(9) Start the engine and allow it to idle for a min-
imum of one minute. With the parking brake applied,
press your foot on the service brake and cycle the
transaxle from park to all gear positions ending in
neutral or park.
(10) Check the transaxle fluid level and add an
appropriate amount to bring the transaxle fluid level
to 3mm (1/8 in.) below the ADD mark on the dip-
stick.
21 - 80 TRANSAXLE AND POWER TRANSFER UNITNS
SERVICE PROCEDURES (Continued)

(11) Recheck the fluid level after the transaxle is
at normal operating temperature. The level should be
in the HOT range. Drive the vehicle a minimum of
10 miles.
(12) Raise the vehicle on the hoist.
(13) Remove the pan and clean all sealant from
the pan and transaxle mating surfaces. Clean the
magnet and the inside of the pan.
(14) Separate the filter from the valve body to
allow additional fluid to drain from the transaxle.
Inspect the filter O-ring for any damage and replace
as necessary.
(15) After the transaxle has stopped draining,
reinstall the filter and O-ring.
(16) Apply a 1/8 inch bead of Mopar RTV Sealant
to the mounting flange of the transaxle oil pan.
Apply RTV Sealant to the underside of the attaching
bolts. Attach the oil pan to the transaxle. Tighten the
bolts to 19 N´m (165 in. lbs.).
(17) Lower the vehicle and add 4 Quarts of Mopar
ATF Plus 3 Type 7176 transaxle fluid.
(18) Start the engine and allow it to idle for a min-
imum of one minute. With the parking brake applied,
press your foot on the service brake and cycle the
transaxle from park to all gear positions ending in
neutral or park.
(19) Check the transaxle fluid level and add an
appropriate amount to bring the transaxle fluid level
to 3mm (1/8 in.) below the ADD mark on the dip-
stick.
(20) Recheck the fluid level after the transaxle is
at normal operating temperature. The level should be
in the HOT range.
FLUID DRAIN AND REFILL
(1) Raise vehicle on a hoist (See Group 0, Lubrica-
tion). Place a drain container with a large opening,
under transaxle oil pan.
(2) Loosen pan bolts and tap the pan at one corner
to break it loose allowing fluid to drain, then remove
the oil pan.
(3) Install a new filter and O-ring on bottom of the
valve body.
(4) Clean the oil pan and magnet. Reinstall pan
using new MOPARtRTV sealant. Tighten oil pan
bolts to 19 N´m (165 in. lbs.).
(5) Pour four quarts of MOPARtATF PLUS 3
(Automatic Transmission Fluid) Type 7176 through
the fill tube.
(6) Start engine and allow to idle for at least one
minute. Then, with parking and service brakes
applied, move selector lever momentarily to each
position, ending in the park or neutral position.(7) Add sufficient fluid to bring level to 1/8 inch
below the ADD mark.
CAUTION: Do not overfill transaxle. Do not add oil
if level is between: Lower holes for warm oil
(100ÉF). Upper holes for hot oil (180ÉF).
(8) Recheck fluid level after transaxle is at normal
operating temperature. The level should be in the
HOT region (Fig. 5).
(9) To prevent dirt from entering transaxle, make
certain that dipstick is seated into the dipstick fill
tube.
ALUMINUM THREAD REPAIR
Damaged or worn threads in the aluminum tran-
saxle case and valve body can be repaired by the use
of Heli-Coils, or equivalent. This repair consists of
drilling out the worn-out damaged threads. Then tap
the hole with a special Heli-Coil tap, or equivalent,
and installing a Heli-Coil insert, or equivalent, into
the hole. This brings the hole back to its original
thread size.
Heli-Coil, or equivalent, tools and inserts are
readily available from most automotive parts suppli-
ers.
FLUSHING COOLERS AND TUBES
When a transaxle failure has contaminated the
fluid, the oil cooler(s) must be flushed. The cooler
bypass valve in the transaxle must be replaced also.
The torque converter must also be replaced with an
exchange unit. This will insure that metal particles
or sludged oil are not later transferred back into the
reconditioned (or replaced) transaxle.
The recommended procedure for flushing the tran-
saxle cooler is to use Tool 6906A Cooler Flusher.
Fig. 5 Oil Level Indicator
NSTRANSAXLE AND POWER TRANSFER UNIT 21 - 81
SERVICE PROCEDURES (Continued)

²The shift lever position must stay until
prompted to shift to overdrive
²The shift lever position must stay in overdrive
after the Shift to Overdrive prompt until the DRBIII
indicates the procedure is complete
²The calculated oil temperature must be above
60É and below 200É
(1) Plug the DRBIII scan tool into the data link
connector. The connector is located under the instru-
ment panel.
(2) Go to the Transmission screen.
(3) Go to the Miscellaneous screen.
(4) Select Quick Learn Procedure. Follow the
instructions of the DRBIII to perform the Quick
Learn Procedure.
PINION FACTOR PROCEDURE
The vehicle speed readings for the speedometer are
taken from the output speed sensor. The TCM must
be calibrated to the different combinations of equip-
ment available. A procedure has been developed
called Pinion Factor. It allows the technician to set
the Transmission Control Module initial setting so
that the speedometer readings will be correct.
Failure to perform this procedure will cause a No
Speedometer Operation condition.
This procedure must be performed if the Transmis-
sion Control Module has been replaced.
To properly read or reset the Pinion Factor, it is
necessary to use a DRBIII scan tool. Perform the fol-
lowing steps with the DRBIII scan tool to read or
reset the Pinion Factor:
(1) Plug the DRBIII scan tool into the data link
connector located under the instrument panel.
(2) Select the Transmission menu.
(3) Select the Miscellaneous menu.
(4) Select Pinion Factor. Then follow the instruc-
tions on the DRBIII scan tool screen.
REMOVAL AND INSTALLATION
GEARSHIFT CABLE
REMOVAL
(1) Remove cable eyelet attachment from transaxle
operating lever pin (Fig. 6).
(2) Using pliers, squeeze ears of cable conduit
attachment at mounting bracket (Fig. 7) and push
through hole to remove (Fig. 8).
(3) Remove the under instrument panel silencer
(Fig. 9). Refer to Group 8E, Instrument Panel And
Gauges for more information.
(4) At the steering column attachment, remove the
cable eyelet attachment from the shift lever pin.(5) Using pliers, squeeze ears of cable attachment
at mounting bracket then push through hole to
remove.
(6) Unseat the dash grommet and remove the
cable from the vehicle.
INSTALLATION
(1) Install cable into steering column attachment
bracket. Verify conduit ears are fully engaged. Verify
cable does not interfere with brake pedal actuation.
(2) Attach cable eyelet fitting onto shift lever pin.
(3) Insert transaxle end of cable through dash
panel hole and fully seat grommet.
(4) Install instrument panel silencer. Verify gear-
shift cable is routed through the slot in the silencer.
CAUTION: Failure to route the cable properly at the
silencer may cause brake pedal interference.
(5) Attach transaxle end of cable to the mounting
bracket on the transaxle. Assure the conduit attach-
ment ears are fully seated.
Fig. 6 Gearshift Cable
Fig. 7 Grommet Clips
NSTRANSAXLE AND POWER TRANSFER UNIT 21 - 83
SERVICE PROCEDURES (Continued)

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

The High Side service port is a two piece port and
is serviceable. The Low Side service port is not ser-
viceable, the suction line would have to be replaced.
REAR BLOWER SPEED SWITCH
The rear blower speed switch controls the rear
blower with the choice of low and high speeds. When
the switch is on it allows the blower speed switch
located on the rear headliner to control rear blower
speed. This switch will override the rear headliner
blower switch. For operation instructions refer to the
Owner's Manual. The rear blower speed switch is
serviced separately from the A/C control module. For
service procedures, refer to Group 8E, Instrument
Panel And Gauges.
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
Fig. 1 A/C Pressure Transducer
Fig. 2 Valve Service Ports
NSHEATING AND AIR CONDITIONING 24 - 3
DESCRIPTION AND OPERATION (Continued)

unit housing. On air conditioned vehicles, the air
passes through the evaporator. At this point the air
flow can be directed either through or around the
heater core. This is done by adjusting the blend- air
door with the TEMP control on the control head. An
optional zone control HVAC control module is avail-
able. This unit has dual blend-air doors that can be
regulated independently of each other. The tempera-
ture setting can be different from driver's side to pas-
senger side. After the air passes the blend-air door(s),
the air flow can then be directed from the Panel,
Floor, and Defrost outlets. Air flow velocity can be
adjusted with the blower speed selector switch on the
control head.
Ambient air intake can be shut off by closing the
recirculating air door. This will recirculate the air
that is already inside the vehicle. This is done by
depressing the Recirc. button on the control head. On
air conditioned vehicles, moving the control to Mix or
Defrost depresses the A/C button and will engage the
compressor. This will send refrigerant through the
evaporator, and remove heat and humidity from the
air before it goes through the heater core.
CAUTION: In cold weather, use of the Recirculation
mode may lead to excessive window fogging. The
Recirculation mode is automatically deactivated in
Mix and Defrost modes to improve window clearing
operation.
SYSTEM OIL LEVEL
It is important to have the correct amount of oil in
the A/C system to ensure proper lubrication of the
compressor. Too little oil will result in damage to the
compressor. Too much oil will reduce the cooling
capacity of the system and consequently result in
higher discharge air temperatures.NOTE: The oil used in the compressor is ND8 PAG
R134a refrigerant oil. Only refrigerant oil of the
same type should be used to service the system.
Do not use any other oil. The oil container should
be kept tightly capped until it is ready for use.
Tightly cap afterwards to prevent contamination
from dirt and moisture. Refrigerant oil will quickly
absorb any moisture it comes in contact with. Spe-
cial 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.
It will not be necessary to check oil level in the
compressor or to add oil unless there has been an oil
loss. Oil loss at a leak point will be evident by the
presence of a wet, shiny surface around the leak.
REFRIGERANT OIL LEVEL CHECK
When an air conditioning system is first assem-
bled, all components (except the compressor) are
refrigerant oil free. After the system has been
charged with R134a refrigerant and operated, the oil
in the compressor is dispersed through the lines and
components. The evaporator, condenser, and filter-
drier will retain a significant amount of oil, refer to
the Refrigerant Oil Capacities chart. When a compo-
nent is replaced, the specified amount of refrigerant
oil must be added. When the compressor is replaced,
the amount of oil that is retained in the rest of the
system must be drained from the replacement com-
pressor. When a line or component has ruptured and
oil has escaped, the compressor should be removed
and drained. The filter-drier must be replaced along
with the ruptured part. The oil capacity of the sys-
tem, minus the amount of oil still in the remaining
components, can be measured and poured into the
suction port of the compressor.
Example: On a dual system the evaporator retains
60 ml (2 oz). The condenser retains 30 ml (1 oz) of
oil, and system capacity may be 220 ml (7.40 oz) of
oil.
220 ml minus 90 ml = 130 ml (4.40 oz).
Fig. 5 Demister Inlet
NSHEATING AND AIR CONDITIONING 24 - 5
DESCRIPTION AND OPERATION (Continued)