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AIR CONDITIONING
1
AIR CONDITIONING
CONTENTS
page
page
AIR CONDITIONING EQUIPMENT . . . . . . . . . . .
AIR CONDITIONING PERFORMANCE TESTS . .
GENERAL INFORMATION . . . . . . . . . . . . . . . . . .
REFRIGERANT LEAK TESTING, DISCHARGING,
EVACUATING AND CHARGING . . . . . . . . . . . .
4
5
1
8
REFRIGERANT OIL . . . . . . . . . . . . . . . . . . . . . . . 9
SERVICE PRECAUTIONS . . . . . . . . . . . . . . . . . . 3
WARNINGS AND CAUTIONS FOR R134A
SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
GENERAL INFORMATION
A/C COMPONENTS
COMPRESSOR—The
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 COIL—They
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.
CONDENSER—The
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-DRIER—The
drier is used to remove con-
taminates and traces of moisture from the refriger-
ant system.
SIGHT-GLASS—The
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
SWITCH—The
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 VALVE—The
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 VALVE—The
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 COIL—The
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 SWITCH—
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 on
XJ
only
THERMOSTAT—The
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 the
YJ
only.
REFRIGERANT LINES—The
lines are used to
carry the refrigerant between the various system
components.
SERVICE PORTS—The
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.
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AIR CONDITIONING
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the operating instructions provided with the equip-
ment for proper operation.
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 to
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.
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AIR CONDITIONING
WARNINGS AND CAUTIONS FOR R134A SYSTEM
3
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.
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AIR CONDITIONING
AIR CONDITIONING EQUIPMENT
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WARNING: EYE PROTECTION MUST BE USED
WHEN SERVICING AN AIR CONDITIONING REFRIG-
ERANT SYSTEM. TURN OFF (ROTATE CLOCKWISE)
ALL VALVES ON THE EQUIPMENT BEING USED
BEFORE PROCEEDING WITH THIS OPERATION.
PERSONNEL INJURY CAN RESULT.
When servicing an air conditioning system, a
R-134a Charging Station and a Recovery/Recycling
Station is required. These devices must meet SAE
standard J2210. Refer to the operating instructions
provided with the equipment for proper operation.
A manifold gauge set (Fig. 1) must also be used
with the Charging and or Recovery/Recycling Station.
The service hoses on the gauge set uses a Quick-Dis-
connect coupler. The coupler has a knob on top which
is used to engage and disengage the sharder valve in
the service port.
MANIFOLD GAUGE SET CONNECTIONS
CAUTION: DO NOT use an R-12 manifold gauge set
on an R-134a system. The refrigerants are not com-
patible and system damage will result.
Fig. 1 Manifold Gauge Set
CONNECTION
(1) Remove the service port cap.
(2) Check all valves on the equipment being used
to verify they are closed.
(3) Attach the Quick-Disconnect coupler to the ser-
vice port and turn knob clockwise to depress sharder
valve.
DISCONNECT
(1) Turn coupler knob counter clockwise to release
sharder valve.
(2) Remove the coupler.
(3) Install the service port cap.
CENTER GAUGE HOSE
The center hose is YELLOW or WHITE with
BLACK STRIP. It is used to recover, evacuate and
charge the refrigerant system. When the low or high
pressure gauge valves on the manifold gauge set are
opened, the refrigerant in the system will escape
through this hose.
This hose attaches to the Recovery/Recycling sta-
tion. Refer to the Recovery/Recycling station Opera-
tors Manual for proper procedures.
LOW PRESSURE GAUGE HOSE
The low pressure hose is BLUE with BLACK
STRIP. The low pressure port is located on the suc-
tion line.
HIGH PRESSURE GAUGE HOSE
The high pressure hose is RED with BLACK
STRIP. The high pressure port is located on the dis-
charge line.
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AIR CONDITIONING
AIR CONDITIONING PERFORMANCE TESTS
5
Humidity has an improtant bearing on the tempra-
ture of the air delivered to the vehicle’s interior. It is
important to understand the effect humidity has on
the performance of the system. When humidity is
high, the evaporator has to perform a double duty. It
must lower the air temperature and the temperature
of the moisture carried in the air. Condensing the
moisture in the air transfers heat energy into the
evaporator fins and tubing. This reduces the amount
of heat the evaporator can absorb from the air. High
humidity greatly reduces the evaporator’s ability to
lower the temperature of the air.
Evaporator capacity used to reduce the amount of
moisture in the air is not wasted. Wringing some of
the moisture out of the air entering the vehicle adds
to the comfort of the passengers. However, an owner
may expect too much from their air conditioning sys-
tem on humid days. A performance test is the best
way to determine whether or not the system is per-
forming up to standard. This test also provides valu-
able clues to the possible cause of trouble.
PERFORMANCE TEST
Air temperature in test room must be 21°C (70°F)
minimum for this test.
(1) Connect a Tachometer and manifold gauge set.
(2) Set A/C controls to Max A/C, temperature lever
on full cool and blower on high.
(3) Start engine and adjust idle to 1,000 RPM with
A/C clutch engaged.
(4) Engine should be warmed up with doors, win-
dows and hood closed.
(5) Insert a thermometer in the left center A/C out-
let. Operate the engine for 5 minutes. The A/C clutch
may cycle depending on ambient temperatures.
(6) After 5 minutes note the discharge air temper-
ature. If the clutch cycles, take the reading before
the clutch disengages.
(7) Open the hood and disconnect vacuum line go-
ing to the heater water control valve. Observe the
valve arm for movement as the line is disconnected.
If it does not move repair vacuum circuit. Plug the
vacuum line to prevent leakage.
(8) Operate the A/C for 2 more minutes and take
the discharge air temperature reading again. On XJ
vehicles if the temperature increased by more than
2°C (5°F) check the blend air door cable for correct
operation.
(9) Compare the discharge air temperature to the
A/C Performance (Temperature and Pressure) Chart.
If discharge air temperature is high, refer to Refrig-
erant Leak Testing and Refrigerant System Diagno-
sis Chart.
(10) Compare the compressor discharge and suc-
tion pressures to the A/C Performance (Temperature
and Pressure) Chart. If the discharge or suction pres-
sure is not normal, check the operation of the refrig-
erant system, referring to Refrigerant System
Diagnosis Chart.
The following charts have been developed for quick
reference.
YJ PERFORMANCE TEMPERATURE AND PRESSURE CHART

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