GMC 1982 Light Duty Truck, Service Manual

Page: 84 / 1435

AIR CONDITIONING IB-41
E V A P O R A T O R B L O W E R -E V A P O R A T O R
SCREEN UPPER CASE
S E N S IN G BULB
E X P A N S IO N E V A P O R A T O R
V A L V E C ORE
Fig. 1 B-40--Expansion Valve
C 6 9
System
2. Install the blower m otor retaining strap and foam.
3. Place the blower m otor and wheel assem bly into the
lower case. Align the blower wheels so th at they do not
contact the case.
4. Place the lower case and blower m otor assem bly in
position in the vehicle and install the lower to upper
case screws.
NOTICE: R otate the blower wheels to m ake sure th at
they do not rub on the case.
5. Install the center ground wire and connect the blower
lead wire.
6. Install the rear duct assem bly as described previously.
7. C onnect the b attery ground cable.
E X P A N S IO N V A LV E
T his sytem incorporates an expansion valve which does
not utilize and external equalizer line (Fig. 1 B-40).
Rem oval
1. Disconnect battery ground cable.
2. Purge the system of refrigerant.
3. Remove the rear duct as outlined previously.
4. D isconnect the blower m otor lead and ground wires.
5. Remove the lower to upper blow er-evaporator case
screws and lower the lower case and motor assembly.
NOTICE: Before removing the case screws, support the
lower case and m otor assem blies to prevent dam age to
the case or m otor assemblies.
6. Remove the expansion valve sensing bulb clamps.
7. D isconnect the valve inlet and outlet lines and remove
the expansion valve assem bly. C ap or plug the open
connections at once.
In sta llation
1. Remove caps or plugs from system connections and
install the new valve assem bly using new " O " rings
coated with clean refrigeration oil.
2. Install the sensing bulb, m aking sure th a t the bulb
m akes good contact with the core outlet line.
3. Install the lower case and blower m otor assemblies.
C onnect the blower m otor lead and ground wires.
4. Install the rear duct as outlined previously.
5. C onnect the b attery ground cable.
6. E vacuate, charge and check the system.
E VA PO R A TO R CORE (Fig. IB -4 0 )
Rem oval
1. Disconnect the battery ground cable.
2. Purge the system or refrigerant.
3. Remove the rear duct as outlined previously.
4. Disconnect the blower motor lead and ground wire
connections.
5. D isconnect the re frig e ra n t lines at the re a r of the
b lo w er-ev ap o rato r assem bly. C ap or plug the open
connections at once.
6. Rem ove the blow er-ev ap o rato r su p p o rt to roof rail
screw s, lower the blow er-ev ap o rato r assem bly and
place it on a work bench upside down.
7. Remove the lower to upper case screws and remove the
lower case assembly. Remove the support to upper case
screws and remove the upper case from the evaporator
core.
8. Remove the expansion valve inlet and outlet lines and
cap or plug the open connections at once. Remove the
expansion valve capillary bulb from the evaporator
outlet line and remove the valve.
9. Remove the plastic pins holding the screen to the core
and remove the screen.
Installation
1. Install the wire screen to the front of the core and insert
the plastic pins.
2. Install the expansion valve inlet and outlet lines using
new " O " rings coated with clean refrigeration oil.
Install the sensing bulb to the evaporator outlet line as
shown in Fig. 1 B-44; m ake sure the bulb has good
contact with the line.
Add 3 oz. clean refrigeration oil when installing a new
core.
3. Install the upper case and supports to the core.
4. Install the lower core case and blower assembly.
5. Install the blow er-evaporator assembly to the roof and
install the support to roof rail screws.
6. Connect the refrigerant lines to the blow er-evaporator
unit using new " O " rings coated w ith clean
refrigeration oil.
7. Connect the blower lead and ground wires.
8. Install the rear duct as outlined previously.
9. Connect the battery ground cable.
Fig. 1B-41--Blower Switch (C-K Overhead System)