Chrysler Stratus Convertible. Manual — part 152

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 refrig-
erant oil is used. Abnormal amounts of dirt, moisture
or air can upset the chemical stability. This may
cause operational troubles or even serious 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.

OPERATION

High pressures are produced in the system when it

is operating. Extreme care must be exercised to make
sure that all connections are pressure tight. Dirt and
moisture can enter the system when it is opened for
repair or replacement 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.

HIGH PRESSURE RELIEF VALVE

DESCRIPTION

The high pressure relief valve is located on the

rear surface of the compressor housing. This mechan-
ical valve is designed to vent refrigerant from the
system to protect against damage to the compressor
and other system components, caused by condenser
air flow restriction or an overcharge of refrigerant.

The high pressure relief valve vents the system

when a discharge pressure of 3445 to 4135 kPa (500
to 600 psi) or above is reached. The valve closes with
a minimum discharge pressure of 2756 kPa (400 psi)
is reached.

The high pressure relief valve is only serviced as

part of the compressor assembly, and must not be
removed or otherwise disturbed.

OPERATION

The high pressure relief valve vents only enough

refrigerant to reduce the system pressure, and then
re-seats itself. The majority of the refrigerant is con-
served in the system. If the valve vents refrigerant, it
does not mean the valve is faulty.

On new compressor assemblies, a mylar disc is

applied to the venting port of the valve. The disc is
primarily intended for protection of the valve during
the painting operation. A missing or damaged disc
does not indicate failure. If the mylar disc has loos-
ened or come off, apply a drop or two of refrigerant
oil into the valve mechanism through the venting
holes. This will prevent salt, dirt, or moisture from
affecting the operation of the valve.

REFRIGERANT

DESCRIPTION

The refrigerant used in this air conditioning sys-

tem is a HydroFluoroCarbon (HFC), type R-134a.
Unlike R-12, which is a ChloroFluoroCarbon (CFC),
R-134a refrigerant does not contain ozone-depleting
chlorine. R-134a refrigerant is a non-toxic, non-flam-
mable, clear, and colorless liquefied gas.

Even though R-134a does not contain chlorine, it

must be reclaimed and recycled just like CFC-type
refrigerants. This is because R-134a is a greenhouse
gas and can contribute to global warming.

OPERATION

R-134a refrigerant is not compatible with R-12

refrigerant in an air conditioning system. Even a
small amount of R-12 added to an R-134a refrigerant
system will cause compressor failure, refrigerant oil
sludge or poor air conditioning system performance.
In addition, the PolyAlkylene Glycol (PAG) synthetic
refrigerant oils used in an R-134a refrigerant system
are not compatible with the mineral-based refriger-
ant oils used in an R-12 refrigerant system.

R-134a refrigerant system service ports, service

tool couplers and refrigerant dispensing bottles have
all been designed with unique fittings to ensure that
an R-134a system is not accidentally contaminated
with the wrong refrigerant (R-12). There are also
labels posted in the engine compartment of the vehi-
cle and on the compressor identifying to service tech-

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HEATING AND AIR CONDITIONING

24 - 5

DESCRIPTION AND OPERATION (Continued)

nicians that the air conditioning system is equipped
with R-134a.

REFRIGERANT SYSTEM SERVICE PORT

DESCRIPTION

The high pressure service port is located on the

discharge line between the compressor and the con-
denser over the cooling fans, near the front of the
engine compartment. The low pressure service port is
located on the suction line, near the right strut
tower.

Each of the service ports has a threaded plastic

protective cap installed over it from the factory. After
servicing the refrigerant system, always reinstall
both of the service port caps.

OPERATION

The two refrigerant system service ports are used

to charge, recover/recycle, evacuate, and test the air
conditioning refrigerant system. Unique service port
coupler sizes are used on the R-134a system, to
ensure that the refrigerant system is not accidentally
contaminated by the use of the wrong refrigerant
(R-12), or refrigerant system service equipment.

SYSTEM AIRFLOW

DESCRIPTION

The system draws outside air through the cowl

opening at the base of the windshield. it flows into
the plenum chamber above the Heater A/C unit hous-
ing and passes through the evaporator. At this point
airflow 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.
After the air passes the blend air door, the air flow is
then directed from the PANEL, BI-LEVEL (panel
and floor), and FLOOR-DEFROST outlets. Air flow
velocity can be adjusted with the blower speed selec-
tor switch on the control head.

OPERATION

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
rotating the RECIRC. knob on the control head.
Rotating the MODE control knob to the Defrost/Floor
or Defrost setting on the control head 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. The com-
pressor can also be engaged by depressing the A/C
button on the control head.

THERMAL LIMITER SWITCH

DESCRIPTION

The thermal limiter switch is used to measure the

compressor surface temperature. If the compressor
surface temperature is excessive, the switch will cut
the battery feed voltage to the compressor clutch coil.
The switch will reset itself, once the compressor sur-
face temperature returns to normal. The switch itself
is not adjustable or serviceable. If faulty the com-
pressor must be replaced.

OPERATION

The thermal limiter switch will interrupt the bat-

tery feed to the compressor clutch coil at a tempera-
ture of about 122 to 128° C (250 to 260° F). The
switch will reset and restore the clutch coil operation
at a temperature of about 104 to 116° C (220 to
240° F).

DIAGNOSIS AND TESTING

A/C PERFORMANCE TEST

The air conditioning system is designed to remove

heat and humidity from the air entering the passen-
ger compartment. The evaporator, located in the
heater A/C unit, is cooled to temperatures near the
freezing point. As warm damp air passes over the
fins in the evaporator, moisture in the air condenses
to water, dehumidifying the air. Condensation on the
evaporator fins reduces the evaporators ability to
absorb heat. During periods of high heat and humid-
ity, an air conditioning system will be less effective.
With the control module set to RECIRC, only air
from the passenger compartment passes through the
evaporator. As the passenger compartment air dehu-
midifies, A/C performance levels rise.

PERFORMANCE TEST PROCEDURE

Review Safety Precautions and Warnings in this

group before proceeding with this procedure. Air tem-
perature in test room and on vehicle must be 21° C
(70°F) minimum for this test.

NOTE: When connecting the service equipment
coupling to the line fitting, verify that the valve of
the coupling is fully closed. This will reduce the
amount of effort required to make the connection.

(1) Connect a tachometer and manifold gauge set.

Attach a thermocouple to the evaporator inlet line.

(2) Set control to A/C, RECIRC, and PANEL, tem-

perature lever on full cool and blower on high.

(3) Start engine and hold at 1000 rpm with A/C

clutch engaged.

24 - 6

HEATING AND AIR CONDITIONING

JX

DESCRIPTION AND OPERATION (Continued)

(4) Engine should be warmed up with doors and

windows closed.

(5) Insert a thermometer or place a thermocouple

in the left center A/C outlet and operate the engine
for five minutes. The A/C clutch may cycle depending
on ambient conditions.

(6) With the A/C clutch engaged, compare the dis-

charge air temperature to the evaporator inlet line
temperature. The evaporator inlet line temperature
should be no more than 5.5°C (10°F) cooler than the
discharge air temperature.

(7) If the discharge air temperature fails to meet

the specifications, refer to the System Charge Level.

COMPRESSOR CLUTCH COIL

(1) Verify battery state of charge.
(2) Connect an ammeter (0-10 ampere scale) in

series with the clutch coil terminal. Use a volt meter
(0-20 volt scale) with clip leads measuring voltage
across the battery and A/C clutch.

(3) With A/C control in A/C mode and blower at

low speed, start the engine and run at normal idle.

(4) The A/C clutch should engage immediately and

the clutch voltage should be within 2 volts of the bat-
tery voltage. If the A/C clutch does not engage, test
the fusible link.

(5) The A/C clutch coil is acceptable if the current

draw is 2.0 to 4.15 amperes at 11.5 to 12.5 volts at
clutch coil. This is with the work area temperature at
21°C (70°F). If voltage is more than 12.5 volts, add
electrical loads by turning on electrical accessories
until voltage reads below 12.5 volts.

(6) If coil current reads zero, the coil is open and

should be replaced. If the ammeter reading is 5
amperes or more, the coil is shorted and should be
replaced. If the coil voltage is not within two volts of
the battery voltage, test clutch coil feed circuit for
excessive voltage drop.

COMPRESSOR NOISE TEST

When investigating an air conditioning related

noise, you must first know the conditions when the
noise occurs. These conditions are: weather, vehicle
speed, in gear or neutral, engine temperature, or any
other special condition.

Noises that develop during air conditioning opera-

tion can often be misleading. For example: what
sounds like a failed front engine bearing or connect-
ing rod, may be caused by loose bolts, nuts, mounting
brackets, or a loose clutch assembly. Improper drive
belt tension can cause a misleading noise when com-
pressor is engaged. The noise may not occur when
compressor is disengaged.

Drive belt(s) are speed sensitive. At different

engine speeds and depending upon belt tension,

belt(s) can develop noises that are mistaken for a
compressor noise.

(1) Select a quiet area for testing. Duplicate condi-

tions as much as possible. Switch compressor on and
off several times to clearly identify compressor noise.
Listen to compressor clutch while engaged and disen-
gaged.

(2) To duplicate high-ambient condition (high-head

pressure), restrict air flow through condenser. Install
manifold gauge set to make sure discharge pressure
doesn’t exceed 2070 kPa (300 psi).

(3) Tighten ALL compressor mounting bolts, clutch

mounting bolt, clutch coil mounting screws

(4) Check refrigerant hoses for rubbing or interfer-

ence which can cause unusual noises.

(5) Check refrigerant charge (refer to Charging the

System).

(6) Check compressor noise as in Step 1.
(7) If noise still exists, loosen compressor mount-

ing bolts and torque. Repeat Step 1.

(8) If noise continues, replace compressor and

repeat Step 1.

CONTROL MODULE

The control switch and timer circuit may be tested

in the vehicle with or without scan tool (DRB).

TESTING WITH SCAN TOOL
If using the scan tool, refer to the proper Body

Diagnostic Procedures Manual.

TESTING WITHOUT SCAN TOOL
(1) Remove the control switch from console and

disconnect control switch (Fig. 2).

(2) Using a ohmmeter, check leads between Pins 5

and 8 of the 8-Way connector. Turn the control mod-
ule to each position shown on Control Module Test
table. The resistance reading should be within the
specifications shown. If not OK, replace the control
module. If OK, check:

• Blown fuse

• Cut wire

• Poor ground

• Poor connection

• Defective BCM

• Bulkhead connector inoperative
Refer to Group 8W, Wiring Diagrams.

HEATER PERFORMANCE TEST

PRE-DIAGNOSTIC PREPARATIONS

Review Safety Precautions and Warnings in this

group before performing the following procedures.

Check the coolant level, drive belt tension, vacuum

line connections, radiator air flow and fan operation.
Start engine and allow to warm up to normal tem-
perature.

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HEATING AND AIR CONDITIONING

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DIAGNOSIS AND TESTING (Continued)

WARNING: DO

NOT

REMOVE

RADIATOR

CAP

WHEN ENGINE IS HOT, PERSONAL INJURY CAN
RESULT.

If vehicle has been run recently, wait 15 minutes

before removing cap. Place a rag over the cap and
turn it to the first safety stop. Allow pressure to
escape through the overflow tube. When the system
stabilizes, remove the cap completely.

MAXIMUM HEATER OUTPUT: TEST AND ACTION

Engine coolant is provided to the heater system by

two 16 mm (5/8 inch inside diameter) heater hoses.
With engine idling at normal running temperature,
set the control to maximum heat, floor, and high
blower setting. Using a test thermometer, check the
air temperature coming from the floor outlets, refer
to Temperature Reference Table.

If the floor outlet air temperature is insufficient,

refer to Group 7, Engine Cooling for specifications.
Both heater hoses should be HOT to the touch (cool-
ant return hose should be slightly cooler than the
supply hose). If coolant return hose is much cooler
than the supply hose, locate and repair engine cool-
ant flow obstruction in heater system.

POSSIBLE LOCATIONS OR CAUSE OF
OBSTRUCTED COOLANT FLOW

(1) Pinched or kinked heater hoses.
(2) Improper heater hose routing.
(3) Plugged heater hoses or supply and return

ports at cooling system connections, refer to Group 7,
Cooling System.

(4) Plugged heater core.
(5) Air locked heater core.
(6) If coolant flow is verified and outlet tempera-

ture is insufficient, a mechanical problem may exist.

POSSIBLE LOCATION OR CAUSE OF INSUFFICIENT
HEAT

(1) Obstructed cowl air intake.
(2) Obstructed heater system outlets.
(3) Blend-air door not functioning properly.

TEMPERATURE CONTROL

If temperature cannot be adjusted with the TEMP

lever on the control panel, the following could require
service:

(1) Blend-air door binding.
(2) Improper engine coolant temperature.
(3) Faulty Instrument Panel Control.

SYSTEM OIL LEVEL

It is important to have the correct amount of lubri-

cant in the A/C system to ensure proper lubrication
of the compressor. Too little lubricant will result in
damage to the compressor. Too much lubricant will
reduce the cooling capacity of the system and conse-
quently result in higher discharge air temperatures.

The lubricant used in the compressor is polyalky-

lene glycol PAG lubricant. Only PAG refrigerant
lubricant approved for use with R-134a should be
used to service the system. Do not use any other
lubricant. The lubricant container should be kept
tightly capped until it is ready for use. Refrigerant
lubricant will quickly absorb any moisture it comes
in contact with.

It is not necessary to check or add lubricant unless

it has been lost. Lubricant loss at the leak point will
be evident by the presence of a wet, shiny surface
around the leak.

Fig. 2 HVAC Control Module Connectors

CONTROL MODULE TEST

SWITCH POSITION

OHM RANGE

Panel

828 to 856 ohms

Bi-Level

1.279 to 1.315 K ohns

Floor

2.302 to 2.358 K ohms

Mix

5.202 to 5.318 K ohms

Defrost

99.5 to 101.5 K ohms

TEMPERATURE REFERENCE TABLE

Ambient

Temp.

Minimum

Floor

Outlet
Temp.

Celsius

Fahrenheit

Celsius

Fahrenheit

15.5°

60°

62.2°

144°

21.1°

70°

63.8°

147°

26.6°

80°

65.5°

150°

32.2°

90°

67.2°

153°

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HEATING AND AIR CONDITIONING

JX

DIAGNOSIS AND TESTING (Continued)