Service Manuals, User Guides, Schematic Diagrams or docs for : . Car Manuals Jeep Cherokee XJ 1988-1989.1993-1995 Approved 1995 XJ Jeep Cherokee 95XJ_24
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J HEATING AND AIR CONDITIONING 24 - 1
HEATING AND AIR CONDITIONING
CONTENTS
page page
COMPONENT SERVICE--XJ VEHICLES . . . . . . 23 REFRIGERANT SERVICE AND PERFORMANCE
COMPONENT SERVICE--YJ VEHICLES . . . . . . 32 TEST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
COMPRESSOR SERVICE . . . . . . . . . . . . . . . . . . 19 TORQUE SPECIFICATIONS . . . . . . . . . . . . . . . . 37
GENERAL INFORMATION . . . . . . . . . . . . . . . . . . 1 WARNINGS, CAUTIONS AND SERVICE
HEATING AND AIR CONDITIONING TEST PRECAUTIONS . . . . . . . . . . . . . . . . . . . . . . . . . 9
PROCEDURES . . . . . . . . . . . . . . . . . . . . . . . . . 15
GENERAL INFORMATION
INDEX
page page
A/C Components . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Refrigerant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Heater and A/C Operation . . . . . . . . . . . . . . . . . . . . 1 Refrigerant Equipment . . . . . . . . . . . . . . . . . . . . . . 7
Manifold Gauge Set . . . . . . . . . . . . . . . . . . . . . . . . 7
HEATER AND A/C OPERATION erate the blend-air door. This door controls air flow
through the core. Vacuum motors are used to actuate
HEATER--XJ and position the remaining door in the system.
A blend-air heating system is used in XJ vehicles. On left hand drive (LHD) XJ vehicles a water valve
The temperature of heated air is controlled by regu- controls coolant flow to the heater core. The valve is
lating the quantity of air flow through the heater vacuum operated. When vacuum is applied, the valve
core. This is accomplished by blending outside air opens and coolant is directed through the heater core
with heated air from the heater core to obtain the de- and back to the engine. When the water valve is
sired discharge temperature. A temperature control closed (no vacuum applied) coolant flow bypasses the
lever on the heater control determines air flow heater core back to the engine.
through the heater core. The lever uses a cable to op-
24 - 2 HEATING AND AIR CONDITIONING J
HEATING SCHEMATIC--XJ
J HEATING AND AIR CONDITIONING 24 - 3
HEATER--YJ The blower motor is operated by the control switch
A blend-air heating system is used in YJ vehicles. (Fig. 1). The switch provides 3 blower speeds for in-
The blend-air system provides a constant flow of en- creased air flow in heat or defrost mode.
gine coolant through the heater core.
DEFROSTING
The heater housing has a defroster door to divert
heated air to the defroster duct and outlets (Fig. 2).
Defrost air flow is controlled by the air control lever.
For defroster operation, the air control lever must
be moved to the defrost detent. The detent is identi-
fied by the defrost symbol on the control panel. In
this position, the defroster door diverts the heated
air from the core to the defroster duct outlets.
If air control lever is moved to any position be-
tween heat and defrost, the defroster door does not
close completely. In this mode, the door remains par-
Fig. 1 Heater Control Panel tially open causing heated air to be divided equally
between the heat and defrost outlets.
The air control lever (Fig. 1) operates a door in the
fresh air intake duct. The door controls the amount FRESH AIR VENTILATION
of fresh air flow into the heater housing and core. The fresh air ventilating system (Fig. 3) is operated
When the lever is in the OFF position, the intake by the air control lever. When the lever is moved to
door is closed preventing air flow into the housing. VENT position, outside air from the cowl intake
The temperature control lever (Fig. 1) determines flows into the heater housing. Incoming air is di-
air flow through the heater core. The lever operates rected into the vehicle interior through vent doors in
the heater housing blend-air door which controls air the housing.
flow through the core. A door in the intake duct controls air flow into the
duct. The door is operated by a vacuum motor. The
Fig. 2 Heating System Components
24 - 4 HEATING AND AIR CONDITIONING J
Fig. 3 Fresh Air Intake System Components
motor is controlled by a vacuum switch in the heater A/C COMPONENTS
control panel. The vent air doors are opened and COMPRESSOR: The SD7H15 Compressor is used
closed by a cable and linkage operated by the air con- on all models. The purpose of the compressor is to
trol lever. Fresh air intake occurs only when the le- compress the low-pressure refrigerant vapor into a
ver is in the VENT position. high pressure, high temperature vapor. The compres-
sor is serviced as a assembly only.
AIR CONDITIONING CLUTCH PULLEY AND COIL: They are
The compressor increases the pressure and temper- mounted on the compressor and providing a way to
ature of the refrigerant. The heated refrigerant vapor drive the compressor. The compressor clutch and coil
is pumped into the condenser where it is cooled by are the only serviced parts on the SD7H15 compres-
air passing over the condenser fins. As the refriger- sor. When the compressor is not in operation, the
ant cools in the condenser, it condenses into a liquid. pulley free wheels on the clutch hub bearing. When
Still under high pressure, the liquid refrigerant the coil is energized the clutch plate is magnetically
passes into the receiver. The receiver acts as a reser- engaged with the pulley and turns the compressor
voir to furnish refrigerant to the expansion valve at shaft.
all times. From the receiver, the high pressure liquid CONDENSER: The condenser is located in front of
refrigerant passes to the expansion valve. The expan- the engine radiator. Its function is to cool the hot
sion valve meters refrigerant into the evaporator. high pressure refrigerant gas. This causes it to con-
The low pressure is maintained by the suction side of dense into high pressure liquid refrigerant.
the compressor. As it enters the evaporator, the re- EXPANSION VALVE: The expansion valve is lo-
frigerant begins to absorb heat from the air passing cated in the engine compartment on XJ vehicles. On
over the evaporator core. Having given up its heat to YJ vehicles it is located behind the A/C housing. Its
boil the refrigerant, the air is cooled and passes into function is to meter refrigerant into the evaporator in
the passenger compartment. From the evaporator the accordance with cooling requirements.
vaporized refrigerant is drawn back to the compres-
sor to repeat the cycle.
J HEATING AND AIR CONDITIONING 24 - 5
AIR CONDITIONING SCHEMATIC--XJ
24 - 6 HEATING AND AIR CONDITIONING J
EVAPORATIVE HOUSING COMPONENTS--YJ
J HEATING AND AIR CONDITIONING 24 - 7
EVAPORATOR COIL: The coil is located in the R-134a refrigerant requires a special type of com-
A/C housing. Its function is to remove heat and de- pressor oil (SP20 PAG). When adding oil, make sure
humidify the air before it enters the vehicle. that it is designed to be used in a R-134a system and
FIN SENSING CYCLING CLUTCH SWITCH: the SD7H15 compressor.
The switch is attached to the evaporator coil with the Service ports have been designed to ensure that
temperature sensing probe inserted into the coil fins. the system is not accidentally filled with R-12 refrig-
This switch controls evaporator temperature and pre- erant.
vents condensate water on the evaporator coil from
freezing. It does this by sending signals to the Pow- REFRIGERANT EQUIPMENT
ertrain Control Module (PCM) to cycling the com-
WARNING: EYE PROTECTION MUST BE USED
pressor clutch on and off. This switch is used on XJ
WHEN SERVICING AN AIR CONDITIONING REFRIG-
only. ERANT SYSTEM. TURN OFF (ROTATE CLOCKWISE)
FILTER-DRIER: The drier is used to remove any ALL VALVES ON THE EQUIPMENT BEING USED
traces of moisture from the refrigerant system. A BEFORE PROCEEDING WITH THIS OPERATION.
sight glass is located on top of the filter drier. It is PERSONNEL INJURY CAN RESULT.
used as a diagnostic tool to observe refrigerant flow.
HIGH PRESSURE RELIEF VALVE: The valve is Chrysler Corporation recommends a (R-134a) recy-
located on the filter drier. The valve is used to pre- cling device that meets SAE standard J2210 be used
vent excessive high pressure build of 3445 to 4135 when servicing the refrigerant system. Contact an
kPa (500 to 600 psi) and above. This prevents dam- automotive service equipment supplier for refrigerant
age to the compressor and other system components. recycling equipment that is available in your area.
LOW-PRESSURE HIGH-PRESSURE CUT-OFF Refer to the operating instructions provided with the
SWITCH: The switch is located on the filter drier recycling equipment for proper operation.
and is wired in series with compressor clutch. When
the pressure drops down to 193 kPa (28 psi) the MANIFOLD GAUGE SET
switch interrupts the power to the compressor clutch.
CAUTION: DO NOT use an R-12 manifold gauge set
When the pressure increases above 3100 to 3375 kPa
on an R-134a system. The refrigerants are not com-
(450 to 490 psi) the switch interrupts the power to patible and system damage will result.
the compressor clutch.
THERMOSTAT: The thermostat is located in the A manifold gauge set (Fig. 1) may be needed in
evaporator housing. The thermostat temperature conjunction with the charging and or recovery/recy-
sensing probe is inserted into the evaporator coil. Its cling device. The service hoses on the gauge set being
function is to cycles the compressor clutch on and off. used should have manual (turn wheel) or automatic
This switch controls temperature and prevents con- back flow valves at the service port connector ends.
densate water on the evaporator coil from freezing. This will prevent refrigerant from being release into
The thermostat is used on the YJ only. the atmosphere.
REFRIGERANT LINES: The lines are used to
carry the refrigerant between the various system LOW PRESSURE GAUGE HOSE
components. The low pressure hose (BLUE with BLACK STRIP)
should be attached to the charging/service port. This
SERVICE PORTS: The high pressure service port
port is located at the right front of the engine com-
is located on the discharge line near the compressor.
partment in the condenser-to-evaporator line.
The low pressure service port is located on the suc-
tion line near the compressor. These ports are used HIGH PRESSURE GAUGE HOSE
to attach A/C gauges. After servicing the refrigerant The high pressure hose (RED with BLACK STRIP)
system, always install service port caps. should be attached to the discharge/service port. This
port is located on the compressor plumbing or mani-
REFRIGERANT fold.
XJ and YJ vehicles use a new type of refrigerant
called R-134a. It is a non-toxic, non-flammable, clear RECOVERY/RECYCLING/EVACUATION/
color-less liquified gas. CHARGING HOSE
R-134a refrigerant is not compatible with R-12 re- The center manifold hose (YELLOW or WHITE
frigerant. A small amount of R-12 in a R-134a system with BLACK STRIP) is used to recover, evacuate and
will cause compressor failure, oil sludge or poor air charge the refrigerant system. When the low or high
conditioning performance. pressure valves on the manifold gauge set are
opened, the refrigerant in the system will escape
through this hose.
24 - 8 HEATING AND AIR CONDITIONING J
Fig. 1 Manifold Gauge Set
Refer to the Recovery/Recycling device operators
manual for proper procedures.
J HEATING AND AIR CONDITIONING 24 - 9
WARNINGS, CAUTIONS AND SERVICE PRECAUTIONS
WARNINGS CAUTIONS
WARNING: THE AIR CONDITIONING SYSTEM CON- CAUTION: Liquid refrigerant is corrosive to metal
TAINS REFRIGERANT UNDER HIGH PRESSURE. surfaces. Follow the operating instructions supplied
SEVERE PERSONAL INJURY MAY RESULT FROM with equipment being used.
IMPROPER SERVICE PROCEDURES. REPAIRS
SHOULD ONLY BE PERFORMED BY QUALIFIED
SERVICE PERSONNEL. CAUTION: DO NOT use R-12 equipment or parts on
the R-134a system. Damage to the system will re-
sult.
WARNING: AVOID BREATHING A/C REFRIGERANT
AND LUBRICANT VAPOR OR MIST. EXPOSURE MAY
CAUTION: Never add R-12 to a system designed to
IRRITATE EYES, NOSE AND/OR THROAT. WEAR
EYE PROTECTION WHEN SERVICING THE AIR use R-134a. Damage to the system will result.
CONDITIONING REFRIGERANT SYSTEM. SERIOUS
EYE INJURY CAN RESULT FROM EYE CONTACT CAUTION: R-12 compressor oil can not be mixed
WITH REFRIGERANT. IF EYE CONTACT IS MADE, with the R-134a compressor oil. They ARE NOT
SEEK MEDICAL ATTENTION IMMEDIATELY. compatible.
WARNING: DO NOT EXPOSE REFRIGERANT TO CAUTION: Do not over charge refrigerant system.
OPEN FLAME. POISONOUS GAS IS CREATED This will cause excessive compressor head pres-
WHEN REFRIGERANT IS BURNED. AN ELEC- sure and can cause noise and system failure.
TRONIC TYPE LEAK DETECTOR IS RECOM-
MENDED.
SERVICE PRECAUTIONS
Recover the refrigerant before opening any fitting
WARNING: IF ACCIDENTAL SYSTEM DISCHARGE or connection. Open fittings with caution even after
OCCURS, VENTILATE THE WORK AREA BEFORE the system has been discharged. Never open or
RESUMING SERVICE. LARGE AMOUNTS OF RE- loosen a connection before recovering the refrigerant.
FRIGERANT RELEASED IN A CLOSED WORK AREA The A/C system must always be evacuated before
WILL DISPLACE THE OXYGEN AND CAUSE SUFFO- charging.
CATION. DO NOT open the refrigerant system or uncap a
replacement component until you are ready to service
the system. This will prevent contamination in the
WARNING: THE EVAPORATION RATE OF (R-134A)
system.
REFRIGERANT AT AVERAGE TEMPERATURE AND Before disconnecting a component clean the outside
ALTITUDE IS EXTREMELY HIGH. AS A RESULT, of the fittings thoroughly to prevent contamination
ANYTHING THAT COMES IN CONTACT WITH THE entering the system.
REFRIGERANT WILL FREEZE. ALWAYS PROTECT Immediately after disconnecting a component from
SKIN OR DELICATE OBJECTS FROM DIRECT CON- the system, seal the open fittings with a cap or plug.
TACT WITH REFRIGERANT. Before connecting an open fitting always install a
new seal/gasket. Coat the fitting and seal with clean
refrigerant oil before connecting.
WARNING: R-134A SERVICE EQUIPMENT OR VEHI-
When installing a refrigerant line avoid sharp
CLE A/C SYSTEM SHOULD NOT BE PRESSURE
bends. Position the lines away from the exhaust or
TESTED OR LEAK TESTED WITH COMPRESSED any sharp edges which may chafe the line.
AIR. SOME MIXTURES OF AIR AND R-134A HAVE Tighten fittings only to the specified torque. The
BEEN SHOWN TO BE COMBUSTIBLE AT ELEVATED aluminum fittings used in the A/C system will not
PRESSURES. THESE MIXTURES ARE POTENTIALLY tolerate over tightening.
DANGEROUS AND MAY RESULT IN FIRE OR EX- When disconnecting a fitting use a wrench on both
PLOSION CAUSING INJURY OR PROPERTY DAM- halves of the fitting. This will prevent twisting of the
AGE. refrigerant lines or tubes.
Refrigerant oil absorbs moisture from the atmo-
sphere if left uncapped. DO NOT open a container of
24 - 10 HEATING AND AIR CONDITIONING J
oil until you are ready to use it. Install the cap im- WARNING: DO NOT STORE IN OPEN OR UN-
mediately after using. Store the oil only in a clean MARKED CONTAINERS.
moisture-free container.
Keep service tools and the work area clean. Con-
tamination of A/C system through careless work hab- WARNING: HOT ENGINE COOLANT CAN CAUSE
its must be avoided. SEVERE BURNS. DO NOT OPEN THE RADIATOR
DRAIN COCK WHEN THE COOLING SYSTEM IS
COOLING SYSTEM HOT AND PRESSURIZED. ALLOW THE COOLANT
To maintain the performance level of the heating/ TO DECREASE TO ROOM TEMPERATURE BEFORE
air conditioning system, the engine cooling system STARTING REPAIR OPERATIONS.
must be properly maintained.
The use of a bug screen is not recommended. Any The engine cooling system is designed to develop
obstructions in front of the radiator or condenser can internal pressure of 97 to 124 kPa (14 to 18 psi). Al-
reduce the performance of the A/C and cooling sys- low the vehicle 15 minutes to cool down (or until a
tem. If a bug screen is used it must be cleaned fre- safe temperature and pressure are attained) before
quently. opening the cooling system. Refer to Group 7, Cooling
System.
COOLANT PRECAUTIONS
REFRIGERANT HOSES/TUBES PRECAUTIONS
WARNING: ANTIFREEZE IS AN ETHYLENE GLYCOL
Kinks or sharp bends in the refrigerant tubing or
BASE COOLANT AND IS HARMFUL IF SWAL-
hoses will reduce the capacity of the entire system.
LOWED OR INHALED. IF SWALLOWED, DRINK
High pressures are produced in the system when it is
TWO GLASSES OF WATER AND INDUCE VOMIT-
ING. IF INHALED, MOVE TO FRESH AIR AREA. operating. Extreme care must be exercised to make
SEEK MEDICAL ATTENTION IMMEDIATELY. sure that all connections are pressure tight. Dirt and
moisture can enter the system when it is opened for
repair.
WARNING: WASH SKIN AND CLOTHING THOR- A good rule for the flexible hose lines is to keep the
OUGHLY AFTER COMING IN CONTACT WITH ETH- radius of all bends at least 10 times the diameter of
YLENE GLYCOL. the hose. Sharp bends will reduce the flow of refrig-
erant. The flexible hose lines should be routed so
WARNING: KEEP OUT OF REACH OF CHILDREN they are at least 80 mm (3 inches) from the exhaust
AND PETS. manifold. It is a good practice to inspect all flexible
hose lines at least once a year to make sure they are
in good condition and properly routed.
WARNING: DO NOT OPEN A COOLING SYSTEM
WHEN THE ENGINE IS AT RUNNING TEMPERA-
TURE. PERSONAL INJURY CAN RESULT.
J HEATING AND AIR CONDITIONING 24 - 11
REFRIGERANT SERVICE AND PERFORMANCE TEST
INDEX
page page
Air Conditioning Performance Tests . . . . . . . . . . . . 12 Leak Testing Refrigerant . . . . . . . . . . . . . . . . . . . . 11
Charging Refrigerant System . . . . . . . . . . . . . . . . . 11 Recovering Refrigerant System . . . . . . . . . . . . . . . 11
Evacuating Refrigerant System . . . . . . . . . . . . . . . 11 Refrigerant Oil . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
LEAK TESTING REFRIGERANT EVACUATING REFRIGERANT SYSTEM
REVIEW WARNINGS AND CAUTIONS IN REVIEW WARNINGS AND CAUTIONS IN
THIS GROUP BEFORE LEAK TESTING. GENERAL INFORMATION SECTION OF THIS
If A/C system is not cooling properly, determine if GROUP BEFORE EVACUATING SYSTEM.
system is fully charged. Refer to Refrigerant System If the A/C system has been open to the atmosphere,
Diagnosis Chart. If the system is empty evacuate the it must be evacuated before the system can be
A/C system and charge system with 0.283 kPa (0.6 charged. Moisture and air mixed with refrigerant will
lbs. or 10 oz.) R-134a refrigerant. Refer to Charging raise the compressor head pressure above acceptable
Refrigerant System for instructions. To detect a leak operating levels. This will reduce the performance of
in the system, perform the following procedures. the air conditioner and damage the compressor. Mois-
(1) Position the vehicle in a wind free work area. ture will boil at near room temperature when ex-
This will aid in detecting small leaks. posed to vacuum. To evacuate the refrigerant system
(2) Bring A/C system up to operating temperature use following procedure:
and pressure. This is done by allowing the engine to (1) Connect a suitable charging station and mani-
run with the A/C on for 5 to 7 minutes. fold gauge set to the vehicle.
(3) Open hood 5 minutes prior to leak test. This (2) Open the low and high side valves and start
will dissipate any accumulated refrigerant in the en- vacuum pump. When suction gauge reads 88 kPa (26
gine compartment. in. Hg) vacuum or greater, close all valves and turn
(4) With the engine not running, use an R-134a off vacuum pump. If system fails to reach specified
Electronic Leak Detector and search for leaks. Move vacuum, the system has a leak that must be cor-
probe slowly along the bottom side of lines and fit- rected. If system maintains the specified vacuum for
tings, because R-134a is heavier than air. Fittings, 30 minutes, start the vacuum pump. Then open the
lines, or components that appear to be oily usually suction and discharge valves and evacuate an addi-
indicates a refrigerant leak. tional 10 minutes.
(5) To inspect the evaporator core for leaks. Set the (3) Close all valves. Turn off and disconnect the
blower at low speed and the selector in PANEL and vacuum pump.
RECIRC mode check for leaks at CENTER panel out- The system is now ready to be charged with refrig-
lets. erant.
RECOVERING REFRIGERANT SYSTEM CHARGING REFRIGERANT SYSTEM
REVIEW WARNINGS AND CAUTIONS IN REVIEW WARNINGS AND CAUTIONS IN
GENERAL INFORMATION SECTION OF THIS GENERAL INFORMATION SECTION OF THIS
GROUP BEFORE DISCHARGING SYSTEM. GROUP BEFORE CHARGING SYSTEM.
R-134a refrigerant is a hydrofluorocarbon (HFC) After the system has been tested for leaks and
that does not contain chlorine. R-134a refrigerant Re- evacuated, a refrigerant charge can be injected into
covery/Recycling Station that meets SAE standard the system. Refer to refrigerant capacities for proper
J2210 must be used to recover the refrigerant. Refer amount of refrigerant charge. Charge the system us-
to the operating instructions provided with the equip- ing a Recovery/Recycling/Charging Station approved
ment for proper operation. for R-134a refrigerant. Refer to the instructions pro-
vided with the equipment for proper operation.
REFRIGERANT CHARGE CAPACITY
The R-134a system charge capacity is 0.9 kPa (32
oz.) for XJ and YJ vehicles.
24 - 12 HEATING AND AIR CONDITIONING J
REFRIGERANT OIL Evaporator capacity used to reduce the amount of
It is important to have the correct amount of oil in moisture in the air is not wasted. Wringing some of
the A/C system. This will ensure proper lubrication of the moisture out of the air entering the vehicle adds
the compressor. Too little oil will result in damage to to the comfort of the passengers. However, an owner
the compressor. Too much oil will reduce the cooling may expect too much from their air conditioning sys-
capacity of the system. tem on humid days. A performance test is the best
The oil used in the SD7H15 compressor is a poly- way to determine whether or not the system is per-
alkylene glycol synthetic oil SP-20 PAG, wax-free re- forming up to standard. This test also provides valu-
frigerant oil. Only refrigerant oil of the same type able clues to the possible cause of trouble.
should be used to service the system. Do not use any Air temperature in test room must be 21◦ Jabse Service Manual Search 2024 ◦ Jabse Pravopis ◦ onTap.bg ◦ Other service manual resources online : Fixya ◦ eServiceinfo