Chevrolet 1977 light duty truck, Service Manual

Page: 102 / 861

1. Disconnect battery g round cable.
2. Purge system o f refrigerant.
3. Disconnect inlet and outlet re frig eran t lines
from the back o f unit. C ap or plug all open connections
at once.
4. Disconnect d ra in tubes from evaporator case.
5. Disconnect electrical connector from com pres­
sor. Remove the te rm inal (See Figure IB-72) and allow
connector to h an g on g round wire.
6. Remove screws securing gro m m et re ta in e r to
dash panel. Remove wire from gro m m et through slit.
7. Disconnect electrical lead at connector.
8. Rem ove unit m ou n tin g bolts. Remove unit from
vehicle, carefully pulling com pressor electrical lead
through dash panel.
Once the unit has been removed from the vehicle,
continue with c om ponent replacem ent as follows:
BLOW ER ASSEMBLY
Removal (Fig. IB -73 )
1. Remove the cover plate an d separate the upper
an d lower case halves. Remove blower motor m ounting
strap screw and remove strap.
2. Rem ove blower assembly. Remove the wheels
from the m otor shaft.
Installation
1. Install the blower wheels on the m otor so that
the lower blades curve toward the dash panel side o f the
unit w hen the m otor is placed in the case as illustrated in
F igure IB-73.
2. Place the motor in the bracket with the electrical
connector side o f the m otor to the right side o f the
bracket. Attach the m o u n tin g strap. Align blower wheels
so that they do not contact case.
3. Assemble the case halves and attach the cover
plate.
Fig. lB-73--ESIower Assem bly (M o to r Home Chassis
U n it)
4. Reverse Steps 1-8 on the "B lower-Evaporator
Assem bly" removal procedure.
5. Evacuate, charge and check the system.
E X P A N S IO N VALVE, EVA PO R A TO R A N D /O R
EVA PO R A TO R CASE
Removal (Fig. IB -7 4 )
1. Remove the cover plate and separate u p p e r and
lower case halves.
2. R em o v e inlet an d outlet lines from the
expansion valve. Remove sensing bulb from the
evaporator outlet manifold. Remove expansion valve.
C ap or plug open connections at once.
3. Remove evaporator core retaining screws and
remove core.
TERMINAL
SCREW DRIVER
(N A R R O W BLADE)
CO NNEC TO R
TA N G
G RO O VE
A. Insert screw driver in groove & press
tang tow ard terminal to release.
B. Pry tang back out to insure locking
when reinstalled into connector.
Fig. lB-74--Expansion Valve (M o to r Home Chassis
U n it)
CORRECT
BLOWER
BLADE
A N G L E
THERMOSTATIC SWITCH SCREEN
CAPILLARY TUBE MESH
BUMPER EXPA N SIO N VALVE