1994 JEEP CHEROKEE Service Repair Manual

INSTALLATION
(1) When installing a replacement temperature
control thermostat, insert the capillary tube into the
evaporator coil a minimum of 50 mm (2 inch) (Fig.
7).
CAUTION: Handle the tube with care to avoid bends
or kinks that could cause the thermostat to mal-
function.
(2) Assemble the housing and install the attaching
screws. DO NOT over tighten the attaching screws.
(3) Install the evaporator housing.
A/C CONDENSER
REMOVAL
WARNING: DO NOT LOOSEN THE RADIATOR
DRAIN COCK WHEN THE COOLING SYSTEM IS
HOT AND PRESSURIZED. HOT COOLANT CAN
CAUSE SERIOUS BURNS.
(1) Discharge the system slowly to prevent loss of
compressor oil.
(2) Drain the radiator. Drain the coolant into a
clean container.
(3) Remove the fan shroud and radiator.
(4) Disconnect the pressure pipe fitting from the
condenser.
(5) Remove the condenser attaching screws and tilt
the bottom of the condenser toward the engine.Plug
all the condenser openings to prevent entry of
dirt or moisture.
(6) Working from under the vehicle, disconnect the
receiver-drier to-evaporator hose fitting from the re-
ceiver-drier.
(7) Remove the condenser and receiver-drier as an
assembly.
(8) Remove the receiver-drier from the condenser,
if necessary.
INSTALLATION
(1) If the condenser is replaced, add 30 ml (1 fluid
oz.) of refrigerant oil to the system.(2) Attach the receiver-drier to the condenser.
(3) Place the condenser in position and connect the
hose fitting to the receiver-drier.
(4) Install the condenser attaching screws.
(5) Connect the condenser pressure pipe fitting.
(6) Install the radiator and fan shroud.
(7) Fill the cooling system.
(8) Evacuate, charge and leak test the air condi-
tioning system.
RECEIVER-DRIER REPLACEMENT
REMOVAL
(1) Discharge the system slowly to prevent loss of
compressor oil.
(2) Disconnect the evaporator and condenser hose
fittings from the receiver-drier.
(3) Remove the receiver-drier attaching screws. Re-
move the receiver-drier.
INSTALLATION
(1) Position the receiver-drier in place. Install and
tighten the receiver-drier attaching screws.
(2) Connect the evaporator and condenser hose fit-
tings to the receiver-drier.
(3) Charge the system.
(4) Preform the leak test on the system.
EVAPORATOR AND HOUSING
REMOVAL
(1) Discharge the system.Discharge the system
slowly to prevent loss of compressor oil.
(2) Disconnect the inlet (suction) hose.
(3) Disconnect the receiver-drier-to-evaporator
hoses.
(4) Remove the hose clamps and dash grommet re-
taining screws.
(5) Remove the evaporator housing-to-instrument
panel attaching screws and the housing mounting
bracket screw (Fig. 8).
Fig. 7 Temperature Control Thermostat
Fig. 8 Evaporator Housing
24 - 42 HEATING AND AIR CONDITIONINGJ

(6) Lower the evaporator housing and pull the
hoses and hose grommet through the dash opening.
The blower motor, blower motor housing, evapora-
tor core, control switches and expansion valve can all
be serviced after removing the evaporator housing
(Fig. 9).
INSTALLATION
(1) If the evaporator is replaced, add 30 ml (1 fluid
oz.) of refrigerant oil to the system.
(2) Push the hoses through the grommet openings
and install the hose grommet by pushing it toward
the engine compartment.
(3) Install the hose grommet attaching screws.
(4) Raise the evaporator housing. Install the evap-
orator housing-to- instrument panel attaching screws
and the evaporator housing mounting bracket screw.
(5) Install the hose clamps.
(6) Connect the receiver-drier hoses.
(7) Connect the inlet (suction) hose.
(8) Evacuate, charge and leak test the system.
EXPANSION (H) VALVE
REMOVAL
(1) Discharge the system slowly to prevent loss of
compressor oil.
(2) Remove the evaporator housing.
(3) Remove the insulation wrapped around the suc-
tion hose fitting, expansion valve and evaporator
tubing.(4) Mark the capillary tube location on the evapo-
rator tubing.
(5) Disconnect the inlet and outlet hose fittings,
and remove the capillary tube clamp.
(6) Disconnect and remove the expansion valve.
INSTALLATION
(1) Clean the evaporator tubing to provide a posi-
tive metal-to-metal contact for the replacement ex-
pansion valve capillary tube.
(2) Install the replacement expansion valve.
(3) Clamp the capillary tube at the marked loca-
tion on the evaporator tubing.
(4) Connect the inlet and outlet hose fittings.The
capillary tube must be securely clamped and
have positive metal-to-metal contact with the
evaporator tubing.
(5) Wrap the expansion valve, inlet hose fitting
and capillary tube with insulation.
(6) Install the evaporator housing.
(7) Evacuate, charge and leak test the system.
A/C BLOWER MOTOR
It is not necessary to discharge the system to ser-
vice the blower motor. The evaporator housing need
only be lowered for access to the blower motor at-
taching screws.
JHEATING AND AIR CONDITIONING 24 - 43

Fig. 9 Evaporative Housing and Components
24 - 44 HEATING AND AIR CONDITIONINGJ

TORQUE SPECIFICATIONS
JHEATING AND AIR CONDITIONING 24 - 45

AIR CONDITIONING
CONTENTS
page page
AIR CONDITIONING EQUIPMENT........... 4
AIR CONDITIONING PERFORMANCE TESTS . . 5
GENERAL INFORMATION.................. 1
REFRIGERANT LEAK TESTING, DISCHARGING,
EVACUATING AND CHARGING............ 8REFRIGERANT OIL....................... 9
SERVICE PRECAUTIONS.................. 3
WARNINGS AND CAUTIONS FOR R134A
SYSTEM.............................. 3
GENERAL INFORMATION
A/C COMPONENTS
COMPRESSORÐThe SD-709 Compressor is used
on all models. The compressor compresses the low-
pressure refrigerant vapor from the evaporator into a
high pressure, high temperature vapor. The compres-
sor is serviced as an assembly only.
CLUTCH PULLEY AND COILÐThey are
mounted on the compressor and providing a way to
drive the compressor. The compressor clutch and coil
are the only serviced parts on the SD-709 compres-
sor. When the compressor is not in operation, the
pulley free wheels on the clutch hub bearing. When
the coil is energized the clutch plate is magnetically
engaged with the pulley and turns the compressor
shaft.
CONDENSERÐThe condenser is located in front
of the engine radiator. Its function is to cool the hot
high pressure refrigerant gas. This causes it to con-
dense into high pressure liquid refrigerant.
FILTER-DRIERÐThe drier is used to remove con-
taminates and traces of moisture from the refriger-
ant system.
SIGHT-GLASSÐThe sight glass is located on top
of the filter drier. It is used as a diagnostic tool to ob-
serve refrigerant flow.
LOW-PRESSURE HIGH-PRESSURE CUT-OFF
SWITCHÐThe switch is located on the filter drier
and is wired in series with compressor clutch. When
the pressure drops down to 193 kPa (28 psi) the
switch interrupts the power to the compressor clutch.
When the pressure increases above 3100 to 3375 kPa
(450 to 490 psi) the switch interrupts the power to
the compressor clutch.
HIGH PRESSURE RELIEF VALVEÐThe valve
is located on the filter drier. The valve is used to pre-
vent excessive pressure up build of 3445 to 4135
kPag (500 to 600 psi) and above. This will prevent
damage to the compressor and other system compo-
nents.EXPANSION VALVEÐThe expansion valve is lo-
cated in the engine compartment on XJ vehicles. On
YJ vehicles it is located behind the A/C housing. Its
function is to meter refrigerant into the evaporator in
accordance with cooling requirements.
EVAPORATOR COILÐThe coil is located in the
A/C housing. Its function is to remove heat and de-
humidify the air before it enters the vehicle.
FIN SENSING CYCLING CLUTCH SWITCHÐ
The switch is attached to the evaporator coil. This
switch prevents condensate water on the evaporator
coil from freezing. It does this by cycling the com-
pressor clutch on and off. This switch is used onXJ
only
THERMOSTATÐThe thermostat is located in the
evaporator housing. Its function is to cycle the com-
pressor clutch to control temperature. The thermo-
stat is used on theYJonly.
REFRIGERANT LINESÐThe lines are used to
carry the refrigerant between the various system
components.
SERVICE PORTSÐThe high pressure service
port is located on the discharge line near the com-
pressor. The low pressure service port is located on
the suction line near the compressor. The compressor
no longer uses service valves.
After servicing the refrigerant system, always in-
stall service port caps.
REFRIGERANT
The vehicles use a new type of refrigerant called
R-134a. It is a non-toxic, non-flammable, clear color-
less liquified gas.
R-134a refrigerant is not compatible with R-12 re-
frigerant in an air conditioning system. A small
amount of R-12 in a R-134a system will cause com-
pressor failure, refrigerant oil sludge or poor A/C per-
formance.
JAIR CONDITIONING1

New service ports are used to ensure that the sys-
tem is not accidentally filled with the wrong refriger-
ant.
Due to the different characteristics of R-134a it re-
quires all new service procedures. Refer to Refriger-
ant Service Procedures in this section before making
any repairs to the air conditioning system.
Chrysler Corporation recommends that a
R-134a refrigerant Recovery/Recycling Station
that meets SAE standard J2210 be used.Refer tothe operating instructions provided with the equip-
ment for proper operation.
REFRIGERANT OIL
R-134a refrigerant requires a special type of com-
pressor oil. The system uses polyalklene glycol syn-
thetic wax-free refrigerant oil SP-20 PAG. No other
oil should be used.
R-12 compressor oil can not be mixed with the
R-134a compressor oil. They ARE NOT compatible.
2 AIR CONDITIONINGJ

WARNINGS AND CAUTIONS FOR R134A SYSTEM
WARNING: AVOID BREATHING A/C REFRIGERANT
AND LUBRICANT VAPOR OR MIST. EXPOSURE MAY
IRRITATE EYES, NOSE AND/OR THROAT. WEAR
EYE PROTECTION WHEN SERVICING THE AIR
CONDITIONING REFRIGERANT SYSTEM. SERIOUS
EYE INJURY CAN RESULT FROM EYE CONTACT
WITH REFRIGERANT. IF EYE CONTACT IS MADE,
SEEK MEDICAL ATTENTION IMMEDIATELY.
WARNING: DO NOT EXPOSE REFRIGERANT TO
OPEN FLAME. POISONOUS GAS IS CREATED
WHEN REFRIGERANT IS BURNED. AN ELEC-
TRONIC LEAK DETECTOR IS RECOMMENDED.
WARNING: IF ACCIDENTAL SYSTEM DISCHARGE
OCCURS, VENTILATE THE WORK AREA BEFORE
RESUMING SERVICE. LARGE AMOUNTS OF RE-
FRIGERANT RELEASED IN A CLOSED WORK AREA
WILL DISPLACE THE OXYGEN AND CAUSE SUFFO-
CATION.
WARNING: THE EVAPORATION RATE OF R-134A
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 DELICATE OBJECTS FROM DIRECT CON-
TACT WITH REFRIGERANT.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 AND R-134A HAVE
BEEN SHOWN TO BE COMBUSTIBLE AT ELEVATED
PRESSURES. THESE MIXTURES ARE POTENTIALLY
DANGEROUS AND MAY RESULT IN FIRE OR EX-
PLOSION CAUSING INJURY OR PROPERTY DAM-
AGE.
CAUTION: Liquid refrigerant is corrosive to metal
surfaces. Follow the operating instructions supplied
with equipment being used.
CAUTION: Never add R-12 to a system designed to
use R-134a. Damage to the system will result.
CAUTION: R-12 compressor oil can not be mixed
with the R-134a compressor oil. They ARE NOT
compatible.
CAUTION: DO NOT use R-12 equipment or parts on
the R-134a system. Damage to the system will re-
sult.
SERVICE PRECAUTIONS
Never open or loosen a connection before discharg-
ing the system refrigerant.
The A/C system must always be evacuated before
charging.
DO NOT open a refrigerant system or uncap a re-
placement component unless it is as close as possible
to room temperature. This will prevent condensation
from forming inside of a component which is cooler
than the surrounding air.
Before disconnecting a component from the system,
clean the outside of the fittings thoroughly.
Immediately after disconnecting a component from
the system, seal the open fittings with a cap or plug.
Before connecting an open fitting always insall a
new seal/gasket. Coat the fitting and seal with clean
refrigerant oil before connecting.
DO NOT remove the sealing caps from a replace-
ment component until ready to install.When installing a refrigerant line avoid sharp
bends. Position the line away from the exhaust or
any sharp edges which may chafe the line.
Tighten fittings only to the specified torque. The
aluminum fittings used in the A/C system will not
tolerate over tightening.
When disconnecting a fitting use a wrench on both
halves of the fitting. This will prevent twisting of the
refrigerant lines or tubes.
Refrigerant oil will absorb moisture from the atmo-
sphere if left uncapped. DO NOT open an oil con-
tainer until ready to use and install the cap
immediately after using. Store the oil only in a clean
moisture-free container.
Keep service tools and the work area clean. Con-
tamination of A/C system through careless work hab-
its must be avoided.
JAIR CONDITIONING3