HEATER
AND AIR
CONDITIONING
1A-55
r-TO COMPRESSOR
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A
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EVAPORATOR
BLOWER
ASM
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-BRACE
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7—-INSTRUMENT PANEL
f REINFORCEMENT
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/
f
R.H. REAR
M
BRACKET
m
K BRACKET—^
#INLET
V
M
"6"
RING
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1
-
DASH PANEL—v
GROMMET—^
\
OUTLET—v
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X
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OUTLET
"O"
RING
A \~-EVAPORATOR
,
&
BLOWER
ASM
INLET
TUBE
Fig.
72—Evaporator Mounting—Universal Unit
9. Replace
the
core
and
valve assembly, with
the
bow-
den cable
in
place,
in the
evaporator case
and
install
the
two
case-to-door bracket attaching screws.
10.
With
the
gasket
in
place, install
the
back cover
of
the evaporator case
and its
attaching screws and
the
seal around
the
evaporator inlet
and
outlet tubes.
11.
Reach through
the
face plate opening
and,
using
the
plastic plug, attach
the
thermostatic switch capillary
tube
to the
evaporator core.
Installation
Within
the Car
1.
Attach system wiring
as
necessary
to the
evaporator
case.
2.
Carefully pass
the
evaporator inlet
and
outlet pipes
through
the
special grommet
in the
dash panel.
3.
Insert
the
evaporator studs through their drilled
holes
in
the
instrument panel flange
and
reinforce-
ment
and,
reaching through
the
glove
box
door
and
ash tray opening, install
the nut
and washer
on
each
stud.
4.
Replace
the
screws attaching
the two
evaporator
case brackets
to
the
blower bracket and distributor
bracket.
5. Replace
the
shield
and
attaching screws protecting
the lower right mounting bracket.
6. Reaching through
the
face plate opening, attach
the
evaporator bowden cable.
7. Replace
the
face plate and attaching screws, feeding
the control knob stems through
the
proper openings
in
the
face plate.
8. Replace
the
control stem bezels
and
control knobs.
9. Replace
the
drain hoses.
10.
Replace
the
glove
box
and
ash
tray.
Under
the
Hood
11.
Replace
the
spacer bracket, screw
and nut on the
CHEVROLET CHASSIS SERVICE /MANUAL
HEATER AND AIR CONDITIONING 1A-56
BLACK & RED
IGNITION—-y^****
SWITCH -"A
/
BLOWER LEAD—^^^
RESISTOR—-" \^<
ASM.
f'
i
'fu^^^^A^^^^^r"G^OUH£>
WIRE
^^
k4
^EVAPORATOR HARNESS
' EVAPORATOR & BLOWER ASM.
Fig.
73—Underdash Wiring—Universal System (Typical)
evaporator outlet pipes. Locate the bracket about
1/2" from the dash panel.
12.
Replace the inlet and outlet hoses and hose clamp
connections.
13.
Evacuate and charge the system. Add three fluid oz.
refrigerent oil after installing a new core.
14.
Check system performance.
Corvette
Replacement (Fig. 78)
1.
Purge the system of refrigerant.
2.
Drain the engine radiator. Then remove the radiator
supply tank from its brackets, the heater water
valve and vacuum line from the firewall, and the
heater hoses from the core pipes. Carefully fold the
hoses,
valve and tank away from the evaporator
case.
3.
Remove the right hand hood lock support.
SCREW DRIVER
(NARROW BLADE) T£
GROOVE
A. Insert screw driver in
tang toward terminal
B. Pry tang back out to
when reinstalled into
RMINAL
\ CONNECTOR
TANG
groove & press
to release.
insure locking
connector.
Fig.
74—Terminal Removal—Universal System
4.
Disconnect the expansion valve equalizer line con-
nection and the evaporator oil bleed line from the
POA.
5.
Disconnect the evaporator outlet to POA inlet
connector.
6. Remove the POA bracket to evaporator case attach-
ing bolts. Then carefully move the valve and its
outlet hose away from the evaporator case.
Fig.
75-Cable Removal-All Weather
CHEVROLET CHASSIS SERVICE MANUAL
HEATER AND AIR CONDITIONING 1A-57
EVAPORATOR PIPES
DISTRIBUTOR RELAY GRD.
ASSEMBLY & WASHER
EVAPORATOR ASM.
BLOWER
SHROUD
(RACKET
(PART OF
BLOWER)
Fig.
76—Evaporator Removal—All Weather
7. Disconnect the thermostatic expansion valve to evap-
orator inlet connector, remove the power element
bulb from the evaporator outlet line and carefully
move .the valve and its inlet hose away from the
evaporator case.
8. Remove the electrical connectors from the relay
and resistor terminals.
9. Remove the screws attaching the evaporator case
cover to the case. See Fig. 79. The core is bracket
mounted to the cover and the entire core and cover
assembly may now be removed from the vehicle.
10.
Remove the two cover to core bracket screws and
separate the core from the cover.
11.
Install the new core to the cover being sure that the
grommets are properly installed around the inlet
and outlet lines.
12.
Reinstall the core and cover assembly into the evap-
orator case and replace the attaching screws.
13.
Reinstall the STV and expansion valves, the equal-
izer line connection and the evaporator oil bleed line
from the STV.
NOTE:
Use all new «O" rings.
14.
Reinstall the radiator supply tank, water valve and
vacuum line, and replace the heater hoses onto the
core pipes being sure not to switch the hoses. Then
refill the radiator.
15.
Add three fluid oz. refrigerant oil after installing a
new core, evacuate and charge the system.
EXPANSION VALVE
The thermostatic expansion valve is factory adjusted
and pre-set and cannot be adjusted after installation. A
malfunctioning valve must be replaced. However, before
proceeding, check all other possible causes of the trouble.
Make certain that the power element bulb is properly
CHEVROLET CHASSIS SERVICE MANUAL
HEATER AND AIR CONDITIONING 1A-58
Fig.
77-Underdash Wiring-All Weather
positioned on the low pressure line, tightly clamped and
has the insulation in place. Make certain the liquid inlet
screen between valve and receiver- dehydrator line is not
clogged. After checking the screen and the location and
mounting of the thermo-bulb, proceed with replacement of
the valve assembly. A malfunctioning valve may result
from a stuck open or shut needle caused by corrosion^ or
a discharged power element caused by a broken capillary
line or tip.
Four-Season System Chevrolet, Chevelle,
Corvette, and Camaro
Replacement
1.
Purge the system and, on Chevelle models, drop
the right fender skirt.
2.
Remove the expansion valve power element bulb
from the low pressure line and the equalizing line
from the POA valve.
3.
Remove the low and high pressure connectors from
the valve, in that order. Remove the screw and
bracket attaching the expansion valve to the blower
case and remove the valve.
4.
Before replacing the valve, check to be certain the
inlet screen, is not clogged. If the screen is plugged,
replace it and check valve operation. If screen is
clear or if valve still malfunctions after screen re-
placement proceed with the valve replacement.
5. Install the new valve by connecting the lines. Clamp
the power element bulb of the new valve to the top of
the low pressure line and the equalizing line to the
suction throttling valve.
NOTE:
Be sure to replace the insulation around
the power element bulb and that the power ele-
ment makes good physical contact with the suc-
tion line.
6. Evacuate and charge the system.
CHEVROLET CHASSIS SERVICE MANUAL
HEATER AND AIR CONDITIONING 1A-59
Fig.
78—Evaporator Mounting (Corvette)
7. Check the system for proper operation.
Universal System
Follow the procedure outlined under " Evaporator" for
the Universal System.
Chevy II All-Weather System
Replacement of Valve Assembly
1.
Purge the system of refrigerant and remove the
evaporator unit from the vehicle and the core from
the unit as described under "Evaporator."
2.
Remove the expansion valve power element bulb and
the equalizing line connection from the low pressure
line.
3.
Remove the low pressure and high pressure lines
from the valve. Remove the valve.
4.
Install the new valve by connecting the low pressure,
high pressure and* equalizing line connections and
clamp the power element of the new valve to the low
pressure line.
5. Replace the core and evaporator as covered under
"Evaporator."
EVAPORATOR CONTROL VALVE (POA)
(Chevrolet, Chevelle, Comoro, Corvette)
No repairs or adjustments are available on the POA
valve. A malfunctioning valve must be replaced. Figures
80,
81, 82 and 83 illustrate valve installation on the above
vehicles.
THERMOSTATIC SWITCH OR BLOWER SWITCH
Universal System
Removal
1.
Remove the screws attaching the cover plate to the
unit and pull the cover rearward.
2.
(Fin sensing type) Remove the thermostatic capillary
tube from the evaporator core to permit access to
the back of the cover plate.
Fig.
79—Evaporator Core Removal (Corvette)
Fig.
80-P.O.A. Installation (Chevrolet)
CHEVROLET CHASSIS SERVICE MANUAL
HEATER AND AIR CONDITIONING 1A-60
Fig.
81-P.O.A. Installation (Camaro)
NOTCH IN SUPPORT
TO ENGAGE SLOT !N VALVE
WHEN VALVE IS ROTATED
TO ANGLE AS SHOWN
Fig.
82-P.O.A. Installation (Chevelle)
Fig.
83—P.O.A. Installation (Corvette)
3.
Remove the electrical connector at the switch to be
replaced.
4.
Remove the switch knob. Remove the switch retain-
ing screws
and:
switch.
Installation
1.
Insert replacement switch into face plate and attach.
2.
Install the switch knob and connect the wiring
connector.
3.
If the thermostatic switch is being replaced, the
capillary tube should be formed to the same shape as
the unit removed.
4.
Attach the capillary to the core (fin sensing type)
and replace the face plate and attaching screws.
CHEVROLET CHASSIS SERVICE MANUAL
HEATER AND AIR CONDITIONING 1A-61
INSERT CAPILLARY
BETWEEN FINS AT
ARROW
Fig.
84—Thermostatic Switch Capillary Installation
All-Weather System (Thermostatic Switch Only)
Chevy II
Replacement (See Fig. 85)
1.
Remove both control knobs and control stem bezels
from the evaporator assembly.
2.
Remove the face plate attaching screws located in
the outer ball outlets and lift off the face plate.
3.
Remove the two thermostatic switch attaching
screws.
4.
Disengage the plastic plug attaching the thermostatic
switch capillary tubing to the face of the evaporator
core (fig. 84).
5. Draw the switch out of the case through the face plate
opening, disconnecting the electrical connectors.
6. Reinstall the new switch by reversing the removal
procedure.
Fig.
85—Thermostatic Switch Removal
unit as outlined under
ALL-WEATHER-PULL CABLE
All-Weather System
Chevy II
Removal
1.
Remove the evaporator
EVAPORATOR.
2.
Remove the screws which attach the front and rear
case halves.
3.
Remove clamp from the evaporator pipes and sep-
arate case halves.
4.
Remove face plate retaining screws located in outer
ball outlets.
5. Remove control knobs and retaining nuts.
6. Remove face plate.
7. Remove cable to case retaining screw and thermo-
static switch mounting screw.
8. Remove evaporator to case mounting screws.
9. Withdraw evaporator with cable and thermostatic
switch assembly. Be careful to prevent kinks in the
thermostatic capillary.
10.
Pull the cable out toward the air outlet side of the
evaporator.
Installation
1.
Pass the replacement cable through the same channel
in the evaporator fins. If a new evaporator is being
installed, a channel will need to be opened between
the evaporator fins. This may be done by pushing a
pointed pencil between the fins beginning at the air
outlet side of the core, two inches to the right of the
left side of the fins and between the third and fourth
tubes down from the top. The cable channel should
exit at the air inlet side of the core between the first
and second tubes down from the top.
CHEVROLET CHASSIS SERVICE MANUAL
HEATER AND AIR CONDITIONING 1A-62
2.
Insert the evaporator assembly into the outlet case
half and mount the evaporator, thermostatic switch,
and cable to the case.
3.
Install the face plate to the case and install control
retaining nuts and knobs.
4.
Assemble the case halves and mount the evaporator
pipe clamp.
5. Install the evaporator assembly as previously
described under EVAPORATOR.
BLOWER ASSEMBLY
Four-Season System
Chevrolet and Camaro
Removal
1.
Disconnect battery ground cable.
2.
Remove the right front fender and skirt assembly.
3.
Disconnect the motor wire at the flange connector.
4.
Disconnect the rubber air cooling tube from the
motor.
5. Remove the motor to case attaching screws and re-
move the blower assembly. If the sealer acts as an
adhesive, pry the assembly carefully away from the
6. Remove the blower from the motor shaft.
Fig.
86—Blower Assembly—Four-Season (Chevrolet,
Chevelle, Camaro)
Installation
1.
Mount the blower to the motor shaft with the open end
of the blower away from the motor.
2.
Mount the assembly to the case with the attaching
screws.
3.
Connect the rubber tube and blower wire to the
motor.
4.
Replace the right front fender and skirt assembly.
5. Connect battery ground cable.
Chevelle
The blower assembly (fig. 86) is mounted to the dash
panel and contains the outside air-recirculated air
diverter door, the heating-cooling diverter door, the air
conditioning relay and resistor, the compressor actuating
switch, and the blower motor.
Replacement
1.
Disconnect the blower motor "hot" wire at the con-
nector and the ground lead on the Chevrolet.
2.
Detach the rubber cooling tube from the blower as-
sembly and remove the five bolts attaching the
blower motor to the blower assembly.
3.
Remove the motor and fan, disassemble fan from
motor and install on a new motor. If, because of
engine accessories, hoses restrict lifting the blower
assembly from the engine compartment, remove
blower from motor and lift units out separately.
Assemble replacement units under the restricting
hoses.
4.
Reinstall motor and fan into blower assembly. Re-
place cooling tube, ground wire and connect hot wire
to connector.
5. Check blower operations.
Corvette
Replacement
1.
Remove the radiator overflow tank and brackets and
pull the tank out of the way as far as the length of the
heater hose will permit.
2.
Disconnect the electrical connector and the rubber
air inlet tube from the blower motor.
3.
Remove the five blower flange to case attaching
screws and carefully remove the blower motor and
drum assembly.
4.
Remove the blower drum assembly and reinstall on
a new blower motor.
5. Replace the blower motor and drum assembly in the
case and reinstall all screws, hoses and electrical
connections.
All-Weather System
Chevy II
Removal
Under the Hood
1.
Purge the refrigerant from the system.
2.
Drain the radiator.
3.
Remove the refrigerant hoses at the evaporator
pipes.
4.
Remove the evaporator pipe clamp and grommet.
5. Remove three nuts from the blower case studs which
pass through the firewall.
6. Remove heater hoses from core tubes.
CHEVROLET CHASSIS SERVICE MANUAL