Chrysler 2004 Concorde Service Manual page 1607

LH
A/C EVAPORATOR (Continued)
High pressures are produced in the refrigerant sys-
tem when the air conditioning compressor is operat-
ing. Extreme care must be exercised to make sure
that each of the refrigerant system connections is
pressure-tight and leak free. It is a good practice to
inspect all flexible hose refrigerant lines at least once
a year to make sure they are in good condition and
properly routed.
(1) Transfer the evaporator probe to the new evap-
orator. Place the evaporator probe in the same loca-
tion as on the previous evaporator(Refer to 24 -
HEATING & AIR
EVAPORATOR TEMPERATURE
INSTALLATION).
(2) Place the evaporator in the lower HVAC hous-
ing.
(3) Insert the access plate inside the HVAC hous-
ing and orientate it so that the locking tab is one-
quarter turn clockwise to where the tab snaps into
the HVAC case detent. Note that the plate will be
flush with the outside of the HVAC housing.
(4) Turn the plate one-quarter turn counter-clock-
wise to seat the locking tab in the HVAC case detent.
(5) Place the top half of the HVAC housing on the
lower half. Tighten fasteners to 2.2 N·m (20 in.
lbs.)(Refer to 24 - HEATING & AIR CONDITION-
ING/DISTRIBUTION/HVAC HOUSING - ASSEM-
BLY).
(6) Install the recirculation door and housing on
the HVAC housing and tighten the screws to 2.2 N·m
(20 in. lbs.).
(7) Install the recirculation door actuator. (Refer to
24 - HEATING & AIR CONDITIONING/CONTROLS/
RECIRCULATION DOOR ACTUATOR - INSTALLA-
TION)
(8) Install the HVAC housing in the vehicle. (Refer
to 24 - HEATING & AIR CONDITIONING/DISTRI-
BUTION/HVAC HOUSING - INSTALLATION)
(9) Evacuate the A/C system(Refer to 24 - HEAT-
ING & AIR CONDITIONING/PLUMBING - STAN-
DARD PROCEDURE).
(10) Charge the A/C system(Refer to 24 - HEAT-
ING & AIR CONDITIONING/PLUMBING - STAN-
DARD PROCEDURE).
A/C EXPANSION VALVE
DESCRIPTION
The "H valve" type thermal expansion valve (TXV)
is located at the point where the refrigerant lines
join the a/c evaporator on the engine compartment
side of the dash panel.
The expansion valve is a factory calibrated unit
and cannot be adjusted or repaired. If faulty or dam-
aged, the expansion valve must be replaced.
CONDITIONING/CONTROLS/
SENSOR
OPERATION
High-pressure, high temperature 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. A temperature sensor in
the expansion valve control head monitors the tem-
perature 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 refrig-
erant into the evaporator coil to meet the vehicle
cooling requirements. Controlling the refrigerant flow
-
through the evaporator ensures that none of the
refrigerant leaving the evaporator is still in a liquid
state, which could damage the compressor.
DIAGNOSIS AND TESTING - A/C EXPANSION
VALVE
The expansion valve can fail in three different
positions (open, closed or restricted). Note, that in
each case, it is defective and requires replace-
ment.
In an Open Position: this will result in a noisy
compressor or no cooling. The cause can be a broken
spring, broken ball or excessive moisture in the A/C
system. If the spring or ball are found to be defective,
replace the expansion valve. If excessive moisture is
found in the A/C system, recycle the refrigerant.
In a Closed Position: There will be low suction
pressure and no cooling. This may be caused by a
failed power dome or excessive moisture in the A/C
system. If the power dome on the expansion valve is
found to be defective replace the expansion valve. If
excessive moisture is found recycle the refrigerant.
A Restricted Orifice: There will be low suction
pressure and no cooling. This may be caused by
debris in the refrigerant system. If debris is believed
to be the cause, recycle the refrigerant and replace
the expansion valve and filter/drier.
REMOVAL
WARNING: REVIEW THE WARNINGS IN THE FRONT
OF THIS SECTION BEFORE PERFORMING THE
FOLLOWING OPERATION. (Refer to 24 - HEATING &
AIR CONDITIONING/PLUMBING - WARNING)
(1) Recover the refrigerant from the system. (Refer
to 24 - HEATING & AIR CONDITIONING/PLUMB-
ING - STANDARD PROCEDURE -REFRIGERANT
RECOVERY)
(2) Remove the engine air inlet tube and the air
distribution duct on vehicles equipped with 3.2/3.5 L
engine(Refer to 9 - ENGINE/AIR INTAKE SYSTEM/
AIR CLEANER ELEMENT - REMOVAL).
PLUMBING 24 - 39