2001 CHRYSLER VOYAGER ECU

contaminated or left open to the atmosphere for an
indeterminable period, it must be replaced.
OPERATION
The filter-drier performs a filtering action to pre-
vent foreign material in the refrigerant from contam-
inating the expansion valve. A desiccant bag is
mounted inside the filter-drier canister to absorb any
moisture which may have entered and become
trapped within the refrigerant system. In addition,
during periods of high demand air conditioner opera-
tion, the filter-drier acts as a reservoir to store sur-
plus refrigerant. Refrigerant enters the filter-drier as
a high-pressure, low-temperature liquid.
REMOVAL
WARNING: REFER TO THE APPLICABLE WARN-
INGS AND CAUTIONS FOR THIS SYSTEM BEFORE
PERFORMING THE FOLLOWING OPERATION.
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - FRONT - WARNING - A/C PLUMBING)
and (Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - FRONT - CAUTION - A/C PLUMBING).
(1) Recover the refrigerant from the refrigerant
system. (Refer to 24 - HEATING & AIR CONDI-
TIONING/PLUMBING - FRONT/REFRIGERANT -
STANDARD PROCEDURE - REFRIGERANT
RECOVERY).
(2) Remove the air cleaner housing from the right
side of the engine compartment.
(3) Remove the screw that secures the liquid line
front section fitting to the top of the filter-drier (Fig.
30).
(4) Disconnect the liquid line fitting from the fil-
ter-drier inlet port.
(5) Remove the seal from the liquid line fitting and
discard.
(6) Install plugs in, or tape over the opened liquid
line fitting and the filter-drier inlet port.
(7) Remove the screw that secures the liquid line
rear section fitting to the top of the filter-drier.
(8) Disconnect the liquid line fitting from the fil-
ter-drier outlet port.
(9) Remove the seal from the liquid line fitting and
discard.
(10) Install plugs in, or tape over the opened liquid
line fitting and the filter-drier outlet port.
(11) Remove the two nuts that secure the filter-
drier mounting bracket to the weld studs on the side
of the right front strut tower.
(12) Remove the filter-drier and mounting bracket
unit from the studs.
INSTALLATION
NOTE: If the filter-drier is being replaced, add 30
milliliters (1 fluid ounce) of refrigerant oil to the
refrigerant system. Use only refrigerant oil of the
type recommended for the compressor in the vehi-
cle.
(1) Position the filter-drier and mounting bracket
unit onto the weld studs on the side of the right front
strut tower (Fig. 30).
(2) Install and tighten the two nuts that secure
the filter-drier mounting bracket to the studs.
Tighten the nuts to 10 N´m (89 in. lbs.).
(3) Remove the tape or plugs from the liquid line
rear section fitting for the filter-drier and the filter-
drier outlet port.
(4) Lubricate a new rubber O-ring seal with clean
refrigerant oil and install it on the liquid line fitting.
(5) Reconnect the liquid line fitting to the filter-
drier outlet port on the top of the filter-drier.
Fig. 30 Front Liquid Lines
1 - A/C GROUND STRAP
2 - NUT
3 - WELD STUD
4 - A/C PRESSURE TRANSDUCER
5 - WELD STUD (2)
6 - EXPANSION VALVE
7 - FRONT LIQUID LINE REAR SECTION
8 - LIQUID LINE EXTENSION (REAR A/C ONLY)
9 - NUT (2)
10 - FILTER-DRIER
11 - ROUTING CLIP
12 - FRONT LIQUID LINE FRONT SECTION
24 - 86 PLUMBING - FRONTRS
RECEIVER/DRIER (Continued)

(6) Install and tighten the screw that secures the
liquid line fitting to the filter-drier. Tighten the screw
to 2 N´m (18 in. lbs.).
(7) Remove the tape or plugs from the liquid line
front section fitting for the filter-drier and the filter-
drier inlet port.
(8) Lubricate a new rubber O-ring seal with clean
refrigerant oil and install it on the liquid line fitting.
(9) Reconnect the liquid line fitting to the filter-
drier inlet port on the top of the filter-drier.
(10) Install and tighten the screw that secures the
liquid line fitting to the filter-drier. Tighten the screw
to 2 N´m (18 in. lbs.).
(11) Reinstall the air cleaner housing into the
right side of the engine compartment.
(12) Evacuate the refrigerant system. (Refer to 24
- HEATING & AIR CONDITIONING/PLUMBING -
FRONT/REFRIGERANT - STANDARD PROCE-
DURE - REFRIGERANT SYSTEM EVACUATE).
(13) Charge the refrigerant system. (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
FRONT/REFRIGERANT - STANDARD PROCE-
DURE - REFRIGERANT SYSTEM CHARGE).
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 refriger-
ants. 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 vehicle and
on the compressor identifying to service techniciansthat the air conditioning system is equipped with
R-134a.
DIAGNOSIS AND TESTING - REFRIGERANT
SYSTEM CHARGE LEVEL
WARNING: REFER TO THE APPLICABLE WARN-
INGS AND CAUTIONS FOR THIS SYSTEM BEFORE
PERFORMING THE FOLLOWING OPERATION.
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - FRONT - WARNING - A/C PLUMBING)
and (Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - FRONT - CAUTION - A/C PLUMBING).
NOTE: The proper amount of R-134a refrigerant for
the refrigerant system in this model is:
²Single or Dual Zone (Front Unit Only)- 0.96
kilograms (2.13 pounds or 34 ounces)
²Three Zone (Front and Rear Units)- 1.31
kilograms (2.88 pounds or 46 ounces)
The procedure that follows should be used to deter-
mine whether the refrigerant system contains the
proper refrigerant charge. Symptoms of an improper
refrigerant charge (low) include: poor air conditioner
performance, fog emitted from the air conditioner
outlets, a hissing sound from the expansion valve/
evaporator area. There are two different methods
with which the refrigerant charge level may be
tested:
²Using a DRBIIItscan tool, a thermocouple and
the Charge Determination Chart (Fig. 31). Refer to
the appropriate diagnostic information.
²Using a manifold gauge set, a thermocouple and
the Charge Determination Chart (Fig. 31).
A temperature probe is required to measure liquid
line temperature. The clamp-on, Type K thermocou-
ple temperature probe used in this procedure is
available through the DaimlerChrysler Professional
Service Equipment (PSE) program. This probe (PSE
#66-324-0014 or #80PK-1A) is compatible with tem-
perature-measuring instruments that accept Type K
thermocouples, and have a miniature connector
input. Other temperature probes are available
through aftermarket sources; however, all references
in this procedure will reflect the use of the probe
made available through the PSE program.
In order to use the temperature probe, a digital
thermometer will also be required. If a digital ther-
mometer is not available, an adapter is available
through the PSE program that will convert any stan-
dard digital multimeter into a digital thermometer.
This adapter is designed to accept any standard Type
K thermocouple. If a digital multimeter is not avail-
able, this tool is also available through the PSE pro-
gram.
RSPLUMBING - FRONT24-87
RECEIVER/DRIER (Continued)

(5) Remove the nut that secures the suction line
fitting to the top of the compressor.
(6) Disconnect the suction line fitting from the
compressor suction port.
(7) Remove the seal from the suction line fitting
and discard.
(8) Install plugs in, or tape over the opened suc-
tion line fitting and the compressor suction port.
(9) Disengage the retainer that secures the suction
line routing clip to the filter-drier mounting bracket
on the side of the right front strut tower in the
engine compartment (Fig. 34).
(10) Remove the nut that secures the suction line
and liquid line fittings to the expansion valve.
(11) Disconnect the suction line and liquid line fit-
tings from the expansion valve.
(12) Remove the seals from the suction line and
liquid line fittings and discard.
(13) Install plugs in, or tape over the opened suc-
tion line and liquid line fittings and both expansion
valve ports.
(14) If the vehicle is equipped with the optional
rear air conditioner, go to Step 15. If the vehicle does
not have the optional rear air conditioner, go to Step
21.
(15) Raise and support the vehicle.(16) Cut the tie strap located just forward of the
connections between the underbody plumbing and
the engine compartment plumbing for the rear
heater and air conditioner (Fig. 35).
(17) Disconnect the suction line extension fitting
from the underbody suction line fitting for the rear
air conditioner.
(18) Remove the seal from the underbody suction
line fitting and discard.
(19) Install plugs in, or tape over the opened suc-
tion line fittings.
(20) Lower the vehicle.
(21) Remove the suction line from the engine com-
partment.
INSTALLATION
The front air conditioner suction line includes the
low side service port on a section of tubing located
near the compressor. On models equipped with the
optional rear air conditioner, the front air conditioner
suction line also includes a suction line hose and
tube extension that connects the front suction line to
the suction line for the rear air conditioner.
WARNING: REFER TO THE APPLICABLE WARN-
INGS AND CAUTIONS FOR THIS SYSTEM BEFORE
PERFORMING THE FOLLOWING OPERATION.
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - FRONT - WARNING - A/C PLUMBING)
and (Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - FRONT - CAUTION - A/C PLUMBING).
Fig. 34 Suction Line
1 - EXPANSION VALVE
2 - SUCTION LINE EXTENSION (REAR A/C ONLY)
3 - NUT
4 - ROUTING CLIP
5 - SUCTION LINE
Fig. 35 Underbody Connections
1 - SUCTION LINE EXTENSION
2 - LIQUID LINE EXTENSION
3 - TIE STRAP
4- HEATER LINE EXTENSIONS
5 - UNDERBODY LINES
RSPLUMBING - FRONT24-93
SUCTION LINE (Continued)

(1) Position the suction line into the engine com-
partment (Fig. 34).
(2) Remove the tape or plugs from the suction line
and liquid line fittings and both expansion valve
ports.
(3) Lubricate new rubber O-ring seals with clean
refrigerant oil and install them on the suction line
and liquid line fittings.
(4) Reconnect the liquid line and suction line fit-
tings to the expansion valve.
(5) Install and tighten the nut that secures the
suction line and liquid line fittings to the expansion
valve. Tighten the nut to 23 N´m (17 ft. lbs.).
(6) Engage the retainer that secures the suction
line routing clip to the filter-drier mounting bracket
on the side of the right front strut tower in the
engine compartment.
(7) Remove the tape or plugs from the compressor
suction port and the suction line fitting.
(8) Lubricate a new rubber O-ring seal with clean
refrigerant oil and install it on the suction line fit-
ting.
(9) Reconnect the suction line fitting to the com-
pressor suction port.
(10) Install and tighten the nut that secures the
suction line fitting to the compressor. Tighten the nut
to 23 N´m (17 ft. lbs.).
(11) Reconnect the drain tube to the wiper module
drain on the right side of the engine compartment.
(12) Reinstall the air cleaner top cover and snorkel
onto the air cleaner housing located on the right side
of the engine compartment.
(13) Reconnect the battery negative cable.
(14) If the vehicle is equipped with the optional
rear air conditioner, go to Step 15. If the vehicle does
not have the optional rear air conditioner, go to Step
21.
(15) Raise and support the vehicle.
(16) Remove the tape or plugs from the suction
line extension fitting and the underbody suction line
fitting (Fig. 35).
(17) Lubricate a new rubber O-ring seal with clean
refrigerant oil and install it on the underbody suction
line fitting.
(18) Reconnect the suction line extension fitting to
the underbody suction line fitting. Tighten the fit-
tings to 23 N´m (17 ft. lbs.).
(19) Install a new tie strap just forward of the con-
nections between the underbody plumbing and the
engine compartment plumbing for the rear heater
and air conditioner.
(20) Lower the vehicle.
(21) Evacuate the refrigerant system. (Refer to 24
- HEATING & AIR CONDITIONING/PLUMBING -
FRONT/REFRIGERANT - STANDARD PROCE-
DURE - REFRIGERANT SYSTEM EVACUATE).(22) Charge the refrigerant system. (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
FRONT/REFRIGERANT - STANDARD PROCE-
DURE - REFRIGERANT SYSTEM CHARGE).
SERVICE PORTS
REMOVAL
WARNING: REFER TO THE APPLICABLE WARN-
INGS AND CAUTIONS FOR THIS SYSTEM BEFORE
PERFORMING THE FOLLOWING OPERATION.
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - FRONT - WARNING - A/C PLUMBING)
and (Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - FRONT - CAUTION - A/C PLUMBING).
(1) Remove the protective cap from the A/C service
port (Fig. 36).
(2) Recover the refrigerant from the refrigerant
system. (Refer to 24 - HEATING & AIR CONDI-
TIONING/PLUMBING - FRONT/REFRIGERANT -
STANDARD PROCEDURE - REFRIGERANT
RECOVERY).
(3) Using a standard Schrader-type valve core tool,
remove the valve core from the A/C service port.
(4) Install a plug in or tape over the opened A/C
service port.
Fig. 36 A/C Service Port - Typical
1 - RIGHT FRONT STRUT TOWER
2 - CONNECTOR
3 - A/C PRESSURE TRANSDUCER
4 - RIGHT WIPER MODULE DRAIN TUBE
5 - HIGH SIDE SERVICE PORT
6 - LIQUID LINE
24 - 94 PLUMBING - FRONTRS
SUCTION LINE (Continued)

PLUMBING - REAR
TABLE OF CONTENTS
page page
EVAPORATOR
DESCRIPTION...........................96
OPERATION.............................96
REMOVAL..............................96
INSTALLATION...........................98
EXPANSION VALVE
DESCRIPTION...........................98
OPERATION.............................98
DIAGNOSIS AND TESTING.................99
EXPANSION VALVE.....................99
REMOVAL..............................99
INSTALLATION...........................99
HEATER CORE
DESCRIPTION..........................100
OPERATION............................100STANDARD PROCEDURE.................100
HEATER CORE FILLING.................100
REMOVAL.............................101
INSTALLATION..........................102
HEATER HOSE
REMOVAL.............................102
INSTALLATION..........................103
SUCTION LINE
REMOVAL.............................103
INSTALLATION..........................104
UNDERBODY LINES
DESCRIPTION..........................105
OPERATION............................105
REMOVAL.............................106
INSTALLATION..........................107
EVAPORATOR
DESCRIPTION
The rear evaporator is located in the rear heater-
A/C unit housing, behind the right rear wheel house.
The evaporator is positioned in the rear heater-A/C
housing so that all air that enters the housing must
pass over the fins of the evaporator before it is dis-
tributed through the system ducts and outlets. How-
ever, air passing over the evaporator fins will only be
conditioned when the compressor is engaged and cir-
culating refrigerant through the evaporator tubes.
The rear heater-A/C unit housing must be removed
from the vehicle to access the evaporator for service.
The evaporator cannot be adjusted or repaired and, if
faulty or damaged, it must be replaced.
OPERATION
Refrigerant enters the rear evaporator from the
rear expansion valve as a low-temperature, low-pres-
sure liquid. As air flows over the fins of the evapora-
tor, the humidity in the air condenses on the fins,
and the heat from the air is absorbed by the refrig-
erant. Heat absorption causes the refrigerant to boil
and vaporize. The refrigerant becomes a low-pressure
gas when it leaves the evaporator.
REMOVAL - REAR EVAPORATOR
WARNING: REFER TO THE APPLICABLE WARN-
INGS AND CAUTIONS FOR THIS SYSTEM BEFORE
PERFORMING THE FOLLOWING OPERATION.(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - FRONT - WARNING - A/C PLUMBING),
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - FRONT - CAUTION - A/C PLUMBING),
and (Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - FRONT - WARNING - HEATER PLUMB-
ING).
(1) Remove the rear heater-A/C unit housing from
the vehicle. (Refer to 24 - HEATING & AIR CONDI-
TIONING/DISTRIBUTION - REAR/REAR HEATER-
A/C HOUSING - REMOVAL).
(2) Remove the rear evaporator line extension from
the expansion valve. (Refer to 24 - HEATING & AIR
CONDITIONING/PLUMBING - REAR/EVAPORA-
TOR - REMOVAL - EVAPORATOR LINE EXTEN-
SION).
(3) Remove the rear expansion valve from the rear
evaporator. (Refer to 24 - HEATING & AIR CONDI-
TIONING/PLUMBING - REAR/EXPANSION VALVE
- REMOVAL).
(4) Remove the rubber grommet that seals the
evaporator inlet and outlet tubes to the rear heater-
A/C housing near the expansion valve.
(5) Remove the three screws that secure the upper
half of the rear heater-A/C housing to the lower half
(Fig. 1).
(6) Remove the three small metal spring clips that
secure the upper half of the rear heater-A/C housing
to the lower half.
(7) Carefully separate and remove the upper half
of the rear heater-A/C housing from the lower half.
24 - 96 PLUMBING - REARRS

(8) Remove the evaporator from the lower half of
the rear heater-A/C housing.
REMOVAL - EVAPORATOR LINE EXTENSION
WARNING: REFER TO THE APPLICABLE WARN-
INGS AND CAUTIONS FOR THIS SYSTEM BEFORE
PERFORMING THE FOLLOWING OPERATION.
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - FRONT - WARNING - A/C PLUMBING),
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - FRONT - CAUTION - A/C PLUMBING),
and (Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - FRONT - WARNING - HEATER PLUMB-
ING).
(1) Remove the rear heater-A/C unit housing from
the vehicle. (Refer to 24 - HEATING & AIR CONDI-
TIONING/DISTRIBUTION - REAR/REAR HEATER-
A/C HOUSING - REMOVAL).
(2) Remove the screw that secures the plate that
captures and seals the evaporator line extension
within the base of the rear heater-A/C unit housing
(Fig. 2).
(3) Remove the capture plate from the rear heater-
A/C unit housing base.
(4) Carefully peel back the expansion valve foam
insulator wrap far enough to access the evaporator
line extension sealing plate on the bottom of the
expansion valve (Fig. 3).
(5) Remove the two screws that secure the expan-
sion valve bracket to the lower rear heater-A/C unit
housing.
(6) Remove the nut that secures the expansion
valve bracket to the expansion valve stud.(7) Remove the expansion valve bracket from the
expansion valve stud.
(8) Remove the nut that secures the evaporator
line extension seal plate to the expansion valve stud.
(9) Remove the evaporator line extension seal
plate from the expansion valve stud.
(10) Remove the evaporator line extension from
the expansion valve and the rear heater-A/C housing
base.
(11) Remove the seals from the evaporator line
extension fittings and discard.
Fig. 1 Rear Evaporator
1 - UPPER REAR HEATER-A/C HOUSING
2 - EVAPORATOR
3 - LOWER REAR HEATER-A/C HOUSING
Fig. 2 Evaporator Line Extension Plate
1 - REAR HEATER-A/C HOUSING BASE
2 - PLATE
3 - EVAPORATOR LINE EXTENSION
Fig. 3 Evaporator Line Extension
1 - UPPER REAR HEATER-A/C HOUSING
2 - LOWER REAR HEATER-A/C HOUSING
3 - EXPANSION VALVE BRACKET
4 - EVAPORATOR LINE EXTENSION
5 - EXPANSION VALVE STUD
6 - INSULATOR WRAP
RSPLUMBING - REAR24-97
EVAPORATOR (Continued)

(12) Install plugs in, or tape over the opened evap-
orator line extension fittings and both expansion
valve ports.
INSTALLATION - REAR EVAPORATOR
NOTE: If the evaporator is being replaced, add 60
milliliters (2 fluid ounces) of refrigerant oil to the
refrigerant system. Use only refrigerant oil of the
type recommended for the compressor in the vehi-
cle.
(1) Carefully lower the evaporator and its foam
wrap into the lower half of the rear heater-A/C hous-
ing.
(2) Position the upper half of the rear heater-A/C
housing onto the lower half (Fig. 1).
(3) Install the three small metal spring clips that
secure the upper half of the rear heater-A/C housing
to the lower half.
(4) Install and tighten the three screws that secure
the upper half of the rear heater-A/C housing to the
lower half. Tighten the screws to 2 N´m (18 in. lbs.).
(5) Install the rubber grommet that seals the evap-
orator inlet and outlet tubes to the rear heater-A/C
housing near the expansion valve.
(6) Reinstall the rear expansion valve onto the
rear evaporator. (Refer to 24 - HEATING & AIR
CONDITIONING/PLUMBING - REAR/EXPANSION
VALVE - INSTALLATION).
(7) Reinstall the rear evaporator extension line
onto the expansion valve. (Refer to 24 - HEATING &
AIR CONDITIONING/PLUMBING - REAR/EVAPO-
RATOR - INSTALLATION - EVAPORATOR EXTEN-
SION LINE).
(8) Reinstall the rear heater-A/C unit housing into
the vehicle. (Refer to 24 - HEATING & AIR CONDI-
TIONING/DISTRIBUTION - REAR/REAR HEATER-
A/C HOUSING - INSTALLATION).
INSTALLATION - EVAPORATOR LINE
EXTENSION
(1) Remove the tape or plugs from the evaporator
line extension fittings and both expansion valve
ports.
(2) Lubricate new rubber O-ring seals with clean
refrigerant oil and install them on the evaporator
line extension fittings.
(3) Position the evaporator line extension to the
expansion valve and the rear heater-A/C housing
base (Fig. 3).
(4) Position the evaporator line extension seal
plate over the expansion valve stud.
(5) Install and tighten the nut that secures the
evaporator line extension seal plate to the expansion
valve stud. Tighten the nut to 23 N´m (17 ft. lbs.).(6) Position the expansion valve bracket over the
expansion valve stud.
(7) Install and tighten the two screws that secure
the expansion valve bracket to the lower rear heater-
A/C unit housing. Tighten the screws to 2 N´m (18 in.
lbs.).
(8) Install and tighten the nut that secures the
expansion valve bracket to the expansion valve stud.
Tighten the nut to 23 N´m (17 ft. lbs.).
(9) Carefully restore the expansion valve foam
insulator wrap back around the expansion valve.
(10) Position the plate that captures and seals the
evaporator line extension onto the rear heater-A/C
unit housing base (Fig. 2).
(11) Install and tighten the screw that secures the
capture plate to the base of the rear heater-A/C unit
housing. Tighten the screw to 2 N´m (18 in. lbs.).
(12) Reinstall the rear heater-A/C unit housing
into the vehicle. (Refer to 24 - HEATING & AIR
CONDITIONING/DISTRIBUTION - REAR/REAR
HEATER-A/C HOUSING - INSTALLATION).
EXPANSION VALVE
DESCRIPTION
The rear ªHº valve-type thermal expansion valve
(TXV) is located at the rear of the rear heater-A/C
unit housing between the evaporator line extension
and the evaporator coil. High-pressure, low tempera-
ture liquid refrigerant from the liquid line passes
through the expansion valve orifice, converting it into
a low-pressure, low-temperature mixture of liquid
and gas before it enters the evaporator coil. Models
equipped with the optional Automatic Temperature
Control (ATC) system also have an electric solenoid
that is located on the inboard side of and integral to
the rear expansion valve. The expansion valve is a
factory calibrated unit and cannot be adjusted or
repaired. If faulty or damaged, the expansion valve
must be replaced.
OPERATION
A mechanical sensor in the expansion valve control
head monitors the temperature and pressure of the
refrigerant leaving the evaporator coil through the
suction line, and adjusts the orifice size at the liquid
line to let the proper amount of refrigerant into the
evaporator coil to meet the vehicle cooling require-
ments. Controlling the refrigerant flow through the
evaporator ensures that none of the refrigerant leav-
ing the evaporator is still in a liquid state, which
could damage the compressor. The expansion valve
solenoid on models equipped with the optional ATC
system electrically blocks refrigerant from passing
through the expansion valve orifice and circulating
24 - 98 PLUMBING - REARRS
EVAPORATOR (Continued)

through the rear evaporator when the rear air condi-
tioner is turned Off.
DIAGNOSIS AND TESTING - EXPANSION VALVE
WARNING: REFER TO THE APPLICABLE WARN-
INGS AND CAUTIONS FOR THIS SYSTEM BEFORE
PERFORMING THE FOLLOWING OPERATION.
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - FRONT - WARNING - A/C PLUMBING)
and (Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - FRONT - CAUTION - A/C PLUMBING).
NOTE: The expansion valve should only be tested
following testing of the compressor.
NOTE: Liquid CO
2is required to test the expansion
valve. This material is available from most welding
supply facilities. Liquid CO
2is also available from
companies which service and sell fire extinguish-
ers.
When testing the expansion valve, the work area
and the vehicle temperature must be 21É to 27É C
(70É to 85É F). To test the expansion valve:
(1) Connect a charging station or manifold gauge
set to the refrigerant system service ports. Verify the
refrigerant charge level.
(2) Close all doors, windows and vents to the pas-
senger compartment.
(3) Set the heater-air conditioner controls so that
the compressor is operating, the temperature control
is in the highest temperature position, the mode door
is directing the output to the floor outlets, and the
blower is operating at the highest speed setting.
(4) Start the engine and allow it to idle at 1000
rpm. After the engine has reached normal operating
temperature, allow the passenger compartment to
heat up. This will create the need for maximum
refrigerant flow into the evaporator.
(5) If the refrigerant charge is sufficient, the dis-
charge (high pressure) gauge should read 965 to 1655
kPa (140 to 240 psi). The suction (low pressure)
gauge should read 140 kPa to 207 kPa (20 psi to 30
psi). If OK, go to Step 6. If not OK, replace the faulty
expansion valve.
WARNING:
PROTECT THE SKIN AND EYES FROM EXPOSURE
TO LIQUID CO
2. PERSONAL INJURY CAN RESULT.
(6) If the suction (low pressure) gauge reads
within the specified range, freeze the expansion valve
control head for 30 seconds using liquid CO
2or
another suitable super-cold material.Do not spray
R-134a or R-12 refrigerant on the expansionvalve control head for this test.The suction (low
pressure) gauge reading should drop by 10 psi. If OK,
go to Step 7 If not OK, replace the faulty expansion
valve.
(7) Allow the expansion valve control head to thaw.
The suction (low pressure) gauge reading should sta-
bilize at 140 kPa to 240 kPa (20 psi to 30 psi). If not
OK, replace the faulty expansion valve.
(8) When expansion valve testing is complete, test
the overall air conditioner performance. (Refer to 24 -
HEATING & AIR CONDITIONING - DIAGNOSIS
AND TESTING - A/C PERFORMANCE TEST).
Remove all test equipment before returning the vehi-
cle to service.
REMOVAL
WARNING: REFER TO THE APPLICABLE WARN-
INGS AND CAUTIONS FOR THIS SYSTEM BEFORE
PERFORMING THE FOLLOWING OPERATION.
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - FRONT - WARNING - A/C PLUMBING),
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - FRONT - CAUTION - A/C PLUMBING),
and (Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - FRONT - WARNING - HEATER PLUMB-
ING).
(1) Remove the rear heater-A/C unit housing from
the vehicle. (Refer to 24 - HEATING & AIR CONDI-
TIONING/DISTRIBUTION - REAR/REAR HEATER-
A/C HOUSING - REMOVAL).
(2) Carefully remove the foam insulator wrap from
the rear expansion valve.
(3) Remove the rear evaporator line extension from
the expansion valve. (Refer to 24 - HEATING & AIR
CONDITIONING/PLUMBING - REAR/EVAPORA-
TOR - REMOVAL - EVAPORATOR LINE EXTEN-
SION).
(4) If the vehicle is equipped with the optional
Automatic Temperature Control (ATC) system, dis-
connect the expansion valve solenoid pigtail wire con-
nector from the rear HVAC wire harness connector
(Fig. 4).
(5) Remove the two screws that secure the expan-
sion valve to the evaporator tube sealing plate.
(6) Remove the expansion valve from the evapora-
tor tubes.
(7) Remove the seals from the evaporator tube fit-
tings and discard.
(8) Install plugs in, or tape over the opened evap-
orator tube fittings and both expansion valve ports.
INSTALLATION
(1) Remove the tape or plugs from the evaporator
tube fittings and both expansion valve ports.
RSPLUMBING - REAR24-99
EXPANSION VALVE (Continued)