2002 CHRYSLER VOYAGER HVAC

system control switch on the front heater-A/C control
is not in the Off position. The blower motor can only
be turned off by turning off the rear system at the
front heater-A/C control. The blower motor receives
battery current whenever the rear blower motor
relay is energized. The rear blower motor relay out-
put circuit is protected by a fuse in the Intelligent
Power Module (IPM) located in the engine compart-
ment near the battery. In the MTC system, the
blower motor speed is controlled by regulating the
path to ground through the blower control switch and
the blower motor resistor. In the ATC system, the
blower motor speed is controlled by an electronic
blower power module, which uses a pulse width mod-
ulated input from the ATC module and feedback from
the blower motor to regulate the blower motor
ground path it provides. The blower motor and wheel
are used to control the velocity of air moving through
the rear heater-A/C unit housing. The blower motor
controls the velocity of the air flowing through the
rear heater-A/C housing by spinning the blower
wheel within the housing at the selected speed or, in
the ATC system, at the selected or programmed
speed.
DIAGNOSIS AND TESTING - BLOWER MOTOR
BLOWER MOTOR INOPERATIVE
(1) Check the fuse (Fuse 12 - 25 ampere) in the
Intelligent Power Module (IPM). If OK, go to Step 2.
If not OK, repair the shorted circuit or component as
required and replace the faulty fuse.
(2) Turn the ignition switch to the On position. Be
certain that the rear heater-A/C control power is
turned on. Check for battery voltage at the fuse
(Fuse 12 - 25 ampere) in the IPM. If OK, go to Step
3. If not OK, proceed to diagnosis of the rear blower
motor relay. (Refer to 24 - HEATING & AIR CONDI-
TIONING/CONTROLS - REAR/BLOWER MOTOR
RELAY - DIAGNOSIS AND TESTING).
(3) Turn the ignition switch to the Off position.
Disconnect and isolate the battery negative cable.
Disconnect the rear HVAC wire harness connector for
the rear blower motor resistor (Manual Temperature
Control) or the rear blower power module (Automatic
Temperature Control) from the resistor or module
connector receptacle. Reconnect the battery negative
cable. Turn the ignition switch to the On position. Be
certain that the rear heater-A/C control power is
turned on. Check for battery voltage at the fused
rear blower motor relay output circuit cavity of the
rear HVAC wire harness connector for the rear
blower motor resistor (MTC) or the rear blower
power module (ATC). If OK, go to Step 4. If not OK,
repair the open fused front blower motor relay output
circuit to the IPM as required.(4) Turn the ignition switch to the Off position.
Disconnect and isolate the battery negative cable.
Disconnect the rear blower motor pigtail wire connec-
tor from the take out and connector of the rear
HVAC wire harness (MTC) or the connector recepta-
cle of the rear blower power module (ATC). Use
jumper wires to connect a battery and ground feeds
to the blower motor pigtail wire connector. The
blower motor should operate. If OK with MTC, pro-
ceed to diagnosis of the rear blower motor resistor.
(Refer to 24 - HEATING & AIR CONDITIONING/
CONTROLS - REAR/BLOWER MOTOR RESISTOR -
DIAGNOSIS AND TESTING). If OK with ATC, use a
DRBIII scan tool to diagnose the rear blower power
module. Refer to the appropriate diagnostic informa-
tion. If not OK with MTC or ATC, replace the faulty
rear blower motor.
BLOWER MOTOR NOISE OR VIBRATION
Refer to the Blower Motor Noise/Vibration Diagno-
sis chart (Fig. 4).
REMOVAL
The rear blower motor and blower wheel are ser-
viced only as a balanced unit. If either component is
faulty or damaged, the entire unit must be replaced.
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) Disconnect the rear blower motor pigtail wire
connector. With manual temperature control, the
blower pigtail wire is connected to a take out and
connector of the rear HVAC wire harness. With auto-
matic temperature control, the blower pigtail wire is
connected to a receptacle on the blower power mod-
ule.
(3) Remove the three screws that secure the
blower motor to the outboard side of the rear heater-
A/C unit housing (Fig. 5).
(4) Remove the blower motor and blower wheel
from the rear heater-A/C unit housing.
RSDISTRIBUTION - REAR24-53
BLOWER MOTOR (Continued)
ProCarManuals.com

INSTALLATION
(1) Position the blower motor and blower wheel
onto the outboard side of the rear heater-A/C unit
housing.
(2) Install and tighten the three screws that secure
the blower motor to the rear heater-A/C unit housing.
Tighten the screws to 2 N´m (18 in. lbs.).
(3) Reconnect the rear blower motor pigtail wire
connector. With manual temperature control, the
blower pigtail wire is connected to a take out and
connector of the rear HVAC wire harness. With auto-
matic temperature control, the blower pigtail wire is
connected to a receptacle on the blower power mod-
ule.
(4) 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).
REAR HEATER-A/C HOUSING
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) Recover the refrigerant from the refrigerant
system. (Refer to 24 - HEATING & AIR CONDI-
TIONING/PLUMBING - FRONT/REFRIGERANT -
STANDARD PROCEDURE - REFRIGERANT
RECOVERY).
(2) Drain the engine cooling system. (Refer to 7 -
COOLING - STANDARD PROCEDURE - COOLING
SYSTEM DRAIN).
(3) Disconnect and isolate the battery negative
cable.
(4) Raise and support the vehicle.
(5) Disconnect the underbody refrigerant line seal-
ing plate from the rear heater-A/C unit evaporator
extension line sealing plate that extends through the
rear floor panel behind the right rear wheel housing
(Fig. 6).
(6) Remove the seals from the liquid line and suc-
tion line fittings and discard.
(7) Install plugs in, or tape over the opened liquid
line and suction line fittings and both ports in the
evaporator extension line sealing plate.
Fig. 5 Blower Motor
1 - REAR HEATER-A/C UNIT HOUSING
2 - BLOWER MOTOR
3 - SCREW (3)
4 - BLOWER PIGTAIL WIRE
Fig. 6 Refrigerant Lines
1 - UNDERBODY REFRIGERANT LINE SEALING PLATE
RSDISTRIBUTION - REAR24-55
BLOWER MOTOR (Continued)
ProCarManuals.com

(8) Remove the three nuts that secure the rear
heater-A/C unit mounting studs to the rear floor
panel behind the right rear wheel housing (Fig. 7).
(9) Lower the vehicle.
(10) Remove the right quarter trim panel and
right D-pillar trim panel from the quarter inner
panel. (Refer to 23 - BODY/INTERIOR/QUARTER
TRIM PANEL - REMOVAL).
(11) Remove the rear A/C distribution duct from
the rear heater-A/C unit and the rear roof duct.
(Refer to 24 - HEATING & AIR CONDITIONING/
DISTRIBUTION - REAR/AUXILIARY A/C DISTRI-
BUTION DUCT - REMOVAL).
(12) Disconnect the body wire harness connector
for the rear heater-A/C unit housing from the rear
HVAC wire harness connector located near the
expansion valve at the back of the unit.
(13) Remove the two screws that secure the top of
the quarter trim panel attaching bracket to the quar-
ter inner panel.
(14) Remove the two screws that secure the bottom
of the quarter trim panel attaching bracket to the
rear heater-A/C unit housing.
(15) Remove the rear heater distribution duct from
the right quarter inner panel. (Refer to 24 - HEAT-
ING & AIR CONDITIONING/DISTRIBUTION -
REAR/REAR HEATER DISTRIBUTION DUCT -
REMOVAL).
(16) Take the proper precautions to protect the
carpeting below the rear heater core from spilled
engine coolant and have absorbent toweling readily
available to clean up any spills.
(17) Disconnect the heater hoses at the rear heater
core. (Refer to 24 - HEATING & AIR CONDITION-
ING/PLUMBING - REAR/HEATER HOSE - REMOV-
AL).(18) Install plugs in, or tape over the opened
heater core fittings and both heater hoses.
(19) Use absorbent toweling to mop up any engine
coolant spills from the preceding operation.
(20) Remove the screw that secures the back of the
rear heater-A/C unit housing to the right D-pillar
(Fig. 8).
(21) Remove the screw that secures the front of
the rear heater-A/C unit housing to the right quarter
inner panel.
(22) Lift the rear heater-A/C unit housing up far
enough for the lower mounting studs and the evapo-
rator extension lines to clear the mounting holes in
the rear floor panel.
(23) Remove the rear heater-A/C unit housing from
the vehicle.
(24) Use absorbent toweling to mop up any engine
coolant spills from the preceding operation.
INSTALLATION
NOTE: If the rear heater core or the rear heater-A/C
housing have been removed from the vehicle for
service, the rear heater core may be pre-filled with
the proper engine coolant mixture prior to recon-
necting the heater hoses to the heater core hose fit-
tings. (Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - REAR/HEATER CORE - STANDARD
PROCEDURE - HEATER CORE FILLING).
(1) Position the rear heater-A/C unit housing into
the vehicle with the evaporator extension line sealing
plate inserted into the rectangular hole in the rear
floor panel behind the right rear wheel house.
(2) Align the rear heater-A/C unit housing lower
mounting studs with the mounting holes in the rear
floor panel and lower the unit to the floor.
(3) Install and tighten the screw that secures the
front of the rear heater-A/C unit housing to the right
quarter inner panel. Tighten the screw to 11 N´m (97
in. lbs.).
(4) Install and tighten the screw that secures the
back of the rear heater-A/C unit housing to the right
D-pillar. Tighten the screw to 11 N´m (97 in. lbs.).
(5) Remove the plugs or tape from both heater core
fittings and both heater hoses.
(6) Reconnect the heater hoses to the rear heater
core. (Refer to 24 - HEATING & AIR CONDITION-
ING/PLUMBING - REAR/HEATER HOSE - INSTAL-
LATION).
(7) Reinstall the rear heater distribution duct onto
the right quarter inner panel. (Refer to 24 - HEAT-
ING & AIR CONDITIONING/DISTRIBUTION -
REAR/REAR HEATER DISTRIBUTION DUCT -
INSTALLATION).
Fig. 7 Rear Heater-A/C Unit Mounting Studs
1 - REAR HEATER-A/C UNIT MOUNTING STUDS
24 - 56 DISTRIBUTION - REARRS
REAR HEATER-A/C HOUSING (Continued)
ProCarManuals.com

(8) Install and tighten the two screws that secure
the bottom of the quarter trim panel attaching
bracket to the rear heater-A/C unit housing. Tighten
the screws to 1.7 N´m (15 in. lbs.).
(9) Install and tighten the two screws that secure
the top of the quarter trim panel attaching bracket to
the quarter inner panel.
(10) Reconnect the body wire harness connector for
the rear heater-A/C unit housing to the rear HVAC
wire harness connector located near the expansion
valve at the back of the unit.
(11) Reinstall the auxiliary A/C distribution duct
onto the rear heater-A/C unit and the rear roof duct.
(Refer to 24 - HEATING & AIR CONDITIONING/
DISTRIBUTION - REAR/AUXILIARY A/C DISTRI-
BUTION DUCT - INSTALLATION).
(12) Reinstall the right quarter trim panel and
right D-pillar trim panel onto the quarter inner
panel. (Refer to 23 - BODY/INTERIOR/QUARTER
TRIM PANEL - INSTALLATION).
(13) Raise and support the vehicle.(14) Install and tighten the three nuts that secure
the rear heater-A/C unit mounting studs to the rear
floor panel behind the right rear wheel housing.
Tighten the nuts to 9 N´m (80 in. lbs.).
(15) Remove the tape or plugs from the underbody
liquid line and suction line fittings and both ports in
the rear heater-A/C unit evaporator extension line
sealing plate that extends through the rear floor
panel behind the right rear wheel housing.
(16) Lubricate new rubber O-ring seals with clean
refrigerant oil and install them on the liquid line and
suction line fittings.
(17) Reconnect the underbody refrigerant line seal-
ing plate to the evaporator extension line sealing
plate.
(18) Install and tighten the screw that secures the
underbody refrigerant line sealing plate to the evap-
orator extension line sealing plate. Tighten the screw
to 23 N´m (17 ft. lbs.).
(19) Lower the vehicle.
(20) Reconnect the battery negative cable.
Fig. 8 Rear Heater-A/C Housing
1 - U-NUT (3)
2 - REAR HEATER-A/C HOUSING
3 - SCREW (3)
4 - EXPANSION VALVE5 - STUD (3)
6 - HEATER LINES
7 - NUT (5)
8 - STUD (2)
RSDISTRIBUTION - REAR24-57
REAR HEATER-A/C HOUSING (Continued)
ProCarManuals.com

(21) Refill the engine cooling system. (Refer to 7 -
COOLING - STANDARD PROCEDURE - COOLING
SYSTEM REFILL).
(22) Evacuate the refrigerant system. (Refer to 24
- HEATING & AIR CONDITIONING/PLUMBING -
FRONT/REFRIGERANT - STANDARD PROCE-
DURE - REFRIGERANT SYSTEM EVACUATE).
(23) Charge the refrigerant system. (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
FRONT/REFRIGERANT - STANDARD PROCE-
DURE - REFRIGERANT SYSTEM CHARGE).
(24) Run the HVAC Cooldown test to verify proper
operation(Refer to 24 - HEATING & AIR CONDI-
TIONING - DIAGNOSIS AND TESTING).
REAR HEATER DISTRIBUTION
DUCT
REMOVAL
(1) Remove the trim from the right quarter inner
panel. (Refer to 23 - BODY/INTERIOR/RIGHT
QUARTER TRIM PANEL - REMOVAL).
(2) Remove the two screws that secure the rear
heater distribution duct to the right quarter inner
panel (Fig. 9).
(3) Slide the rear heater distribution duct forward
far enough to disengage it from the outlet on the
front of the rear heater-air conditioner unit housing.
(4) Remove the rear heater distribution duct from
the vehicle.
INSTALLATION
(1) Align the inlet end of rear heater distribution
duct with the outlet on the front of the rear heater-
air conditioner unit housing.(2) Slide the rear heater distribution duct rear-
ward far enough to fully engage the inlet end of the
duct with the outlet on the front of the rear heater-
air conditioner unit housing.
(3) Install and tighten the two screws that secure
the rear heater distribution duct to the right quarter
inner panel. Tighten the screws to 1.6 N´m (14 in.
lbs.).
(4) Reinstall the trim onto the right quarter inner
panel. (Refer to 23 - BODY/INTERIOR/RIGHT
QUARTER TRIM PANEL - INSTALLATION).
Fig. 9 Rear Heater Distribution Duct
1 - REAR HEATER DISTRIBUTION DUCT
2 - REAR HEATER-A/C UNIT OUTLET
3 - SCREW (2)
24 - 58 DISTRIBUTION - REARRS
REAR HEATER-A/C HOUSING (Continued)
ProCarManuals.com

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
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 HVAC unit housing from the vehi-
cle. (Refer to 24 - HEATING & AIR CONDITION-
ING/DISTRIBUTION - FRONT/HVAC HOUSING -
REMOVAL).
(2) Remove the heater core tubes from the heater
core. (Refer to 24 - HEATING & AIR CONDITION-
ING/PLUMBING - FRONT/HEATER CORE -
REMOVAL - HEATER CORE TUBES).
(3) Remove and discard the foam seal from the
HVAC housing seal flange around the fresh air inlet
opening and the expansion valve/evaporator tube
opening on the dash panel side of the unit.
(4) Remove the expansion valve from the evapora-
tor inlet and outlet tube fittings. (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
FRONT/EXPANSION VALVE - REMOVAL).
(5) Disconnect the HVAC wire harness connector
for the blower motor from the motor connector recep-
tacle on the bottom of the outboard end of the evap-
orator housing.
(6) Disengage the HVAC wire harness from the
routing clips molded into the outside of the HVAC
housing components.
(7) Remove the three screws from the dash panel
side of the unit that secure the top of the distribution
housing to the inboard end of the evaporator housing
(Fig. 9).
(8) Pull the top of the distribution housing away
from the evaporator housing far enough to disengage
the two hook formations on the bottom of the distri-
bution housing from the two receptacles on the evap-
orator housing (Fig. 10).
(9) Remove the two screws that secure the upper
intake air housing to the lower intake air housing.
(10) Remove the three screws that secure the
upper intake air housing to the top of the outboard
end of the evaporator housing. Be certain not to miss
the screw located just inside the inboard side of the
fresh air intake opening.(11) Remove the upper intake air housing from the
top of the evaporator housing to expose the recircu-
lation air door and the blower wheel housing (Fig.
11).
(12) Remove the two screws that secure the upper
half of the recirculation air door to the lower half of
the door.
(13) Remove the upper half of the recirculation air
door from the lower half of the door (Fig. 12).
(14) Remove the twelve screws around the perime-
ter of the evaporator housing that secure the upper
housing half to the lower half.
Fig. 9 HVAC Housing
1 - DISTRIBUTION HOUSING
2 - SCREWS (3)
3 - HVAC WIRING HARNESS
4 - ROUTING CLIP
5 - EVAPORATOR HOUSING
Fig. 10 Distribution Housing Hooks
1 - RECEPTACLES ON EVAPORATOR HOUSING
2 - HOOKS ON DISTRIBUTION HOUSING
RSPLUMBING - FRONT24-69
EVAPORATOR (Continued)
ProCarManuals.com

(15) Carefully separate and remove the upper half
of the evaporator housing from the lower half. Be cer-
tain not to lose the rubber grommet for the HVAC
wire harness evaporator temperature sensor take
out. This grommet is located on the inboard side of
the flange around the expansion valve/evaporator
tube opening on the dash panel side of the unit,
where it is captured in a notched area between the
upper and lower housing halves (Fig. 13).(16) Carefully lift the evaporator and its foam
wrap out of the lower half of the evaporator housing
as a unit. Be certain not to lose the clam shell type
rubber seal that is fitted to the evaporator inlet and
outlet tubes where they exit the evaporator housing.
INSTALLATION
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 evaporator housing as
a unit. Be certain that the clam shell type rubber
seal is fitted to the evaporator inlet and outlet tubes
where they exit the evaporator housing.
(2) Position the upper half of the evaporator hous-
ing onto the lower half. Be certain that the rubber
grommet and the HVAC wire harness take out for
the evaporator temperature sensor are captured in
the notched area between the upper and lower hous-
ing halves.
(3) Install and tighten the twelve screws around
the perimeter of the evaporator housing that secure
the upper housing half to the lower half. Tighten the
screws to 2 N´m (18 in. lbs.).
(4) Position the upper half of the recirculation air
door onto the lower half of the door.
(5) Install and tighten the two screws that secure
the upper half of the recirculation air door to the
Fig. 11 Upper Intake Air Housing
1 - EVAPORATOR HOUSING
2- UPPER INTAKE AIR HOUSING
3 - RECIRCULATION AIR DOOR
4 - BLOWER WHEEL
Fig. 12 Recirculation Air Door
1 - EVAPORATOR HOUSING
2 - UPPER RECIRCULATION AIR DOOR
3 - LOWER INTAKE AIR HOUSING
Fig. 13 Evaporator Housing
1 - LOWER EVAPORATOR HOUSING
2 - UPPER EVAPORATOR HOUSING
3 - BLOWER WHEEL
4 - EVAPORATOR
24 - 70 PLUMBING - FRONTRS
EVAPORATOR (Continued)
ProCarManuals.com

lower half of the door. Tighten the screws to 2 N´m
(18 in. lbs.).
(6) Position the upper intake air housing onto the
top of the evaporator housing over the recirculation
air door and the blower wheel housing. Be certain
that the upper pivot of the recirculation air door is
captured in the pivot receptacle of the upper intake
air housing.
(7) Install and tighten the three screws that secure
the upper intake air housing to the top of the out-
board end of the evaporator housing. Be certain not
to miss the screw located just inside the inboard side
of the fresh air intake opening. Tighten the screws to
2 N´m (18 in. lbs.).
(8) Install and tighten the two screws that secure
the upper intake air housing to the lower intake air
housing. Tighten the screws to 2 N´m (18 in. lbs.).
(9) Engage the two hook formations on the bottom
of the distribution housing in the two receptacles on
the evaporator housing.
(10) Roll the top of the distribution housing up
into position against the evaporator housing.
(11) Install and tighten the three screws from the
dash panel side of the unit that secure the top of the
distribution housing to the inboard end of the evapo-
rator housing. Tighten the screws to 2 N´m (18 in.
lbs.).
(12) Engage the HVAC wire harness in the routing
clips molded into the outside of the HVAC housing
components.
(13) Reconnect the HVAC wire harness connector
for the blower motor with the motor connector recep-
tacle on the bottom of the outboard end of the evap-
orator housing.
(14) Reinstall the expansion valve onto the evapo-
rator inlet and outlet tube fittings. (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
FRONT/EXPANSION VALVE - INSTALLATION).
(15) Install a new foam seal onto the HVAC hous-
ing seal flange around the fresh air inlet opening and
the expansion valve/evaporator tube opening on the
dash panel side of the unit.
(16) Reinstall the heater core tubes into the heater
core. (Refer to 24 - HEATING & AIR CONDITION-
ING/PLUMBING - FRONT/HEATER CORE -
INSTALLATION - HEATER CORE TUBES).
(17) Reinstall the HVAC unit housing into the
vehicle. (Refer to 24 - HEATING & AIR CONDI-
TIONING/DISTRIBUTION - FRONT/HVAC HOUS-
ING - INSTALLATION).
(18) Run the HVAC Control Actuator Calibration
procedure(Refer to 24 - HEATING & AIR CONDI-
TIONING - DIAGNOSIS AND TESTING)(Refer to 24
- HEATING & AIR CONDITIONING - DIAGNOSIS
AND TESTING).EXPANSION VALVE
DESCRIPTION
The front ªHº valve-type thermal expansion valve
(TXV) is located at the dash panel between the liquid
and suction lines, and the evaporator coil. The
assembly consists of an H-valve body and a thermal
sensor. High-pressure, low temperature liquid refrig-
erant from the liquid line passes through the expan-
sion valve orifice, converting it into a low-pressure,
low-temperature mixture of liquid and gas before it
enters the evaporator coil. 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 thermo sensor
measures refrigerant suction gas temperature which
is monitored by the a/c control assembly.
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 is required to test the expansion
valve. This material is available from most welding
supply facilities. Liquid CO is 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.
RSPLUMBING - FRONT24-71
EVAPORATOR (Continued)
ProCarManuals.com