
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-64
Fig.
90—Evaporator Wiring (Corvette)
AIR INLET VALVE
Four-Season System
Chevrolet
Figure 88 illustrates the vacuum valve which controls
the air inlet operation of the Four-Season System.
A vacuum tank and check valve is used to assure that
the air door will not change its position due to variations
in engine vacuum.
Camqro
Figure 89 illustrates the outside air inlet door assem-
bly, and the door in the kick pad which admits reeir-
culated air to the system.
BLOWER AND EVAPORATOR ASSEMBLY
(Corvette)
Replacement
1.
Remove the evaporator core as outlined under
"Evaporator Core Replacement".
2.
Remove the blower motor as outlined under "Blower
Motor Replacement".
3.
Remove the heater and air conditioning distributor
as outlined under "Air Distributor Duct Removal".
4.
Remove the remaining nuts attaching the blower
and evaporator assembly and the cover assembly
to the studs on the -firewall.
5. Replace the components removed by reversing the
removal, procedure.
AIR DISTRIBUTOR ASSEMBLY
AND OUTLET DUCTS
Four Season System
Chevrolet and Chevelle
Figures 92 through .95 illustrate the air distributor and
outlet ducts as used in the Chevrolet, Chevelle, Camaro,
and Corvette.
Corvette
Right Outlet Duct
Removal
1.
Remove the clamp screw at the inner end of the
outlet duct and loosen the clamp.
2.
Remove the screw and lock washer attaching the
duct outer mounting tab to the body hinge pillar
brace.
3.
Pull the duct and clamp down and away from the
distributor assembly. Disconnect the courtesy light.
4.
The duct extension assembly may now be removed
if desired as well as the deflector assembly. See
Figure 95.
AIR COND.
PULL
AIR PULL- DEFROSTER
FAN PULL HOT PULL
Fig.
91—Corvette Four-Season Controls
CHEVROLET CHASSIS SERVICE MANUAL

HEATER AND AIR CONDITIONING 1A-65
Fig.
92—Chevrolet Four-Season Ducts
Installation
Reverse
assembly.
the removal procedure to reinstall the duct
Left Outlet Duct
Removal
1.
Remove the two parking brake lever bracket to
dash brace attaching screws and move the lever and
cable so they will not interfere with the duct
removal.
2.
Remove the screw and lock washer attaching the duct
outer bracket to the hinge pillar support.
3.
Remove the screws and lock washers attaching the
duct assembly to the dash brace bracket.
4.
Carefully pull the outer end of the duct downward,
detaching the courtesy light from its bracket.
5. Loosen the screws clamping the outlet duct to dis-
tributor assembly flexible tubing at the outlet duct.
The outlet duct may now be removed from beneath
the instrument panel.
6. The duct extension assembly and the deflector as-
sembly may be removed, if desired, as seen in
Figure 95.
Installation
The duct assembly is installed by reversing the re-
moval instructions.
Center Outlet Duct
Removal
1.
Remove the right and left console trim panels.
2.
Remove the radio receiver.
3.
Remove the electric clock.
4.
Remove the knobs, nuts and bezels from the two
air conditioning controls above the clock, AIR COND.
PULL and COLD IN-HOT PULL.
5. Carefully pull the outlet duct and control cables
loose from the rear of the center console and work
it down and out from under the dash. The left hand
control cable runs through the left hand flexible
tubing and may be left in the tubing after it is dis-
engaged from the duct. The right hand control cable
must also be pulled from the duct assembly as the
duct is removed.
6. The center deflector barrel assembly may now be
removed if necessary. Snap off the hairpin clips to
remove the barrel and spacer washers.
Installation
Reverse the removal procedure for installation.
AIR DISTRIBUTOR ASSEMBLY
Removal
1.
Drain the cooling system radiator.
2.
Remove the heater hoses from the core pipes and
remove the cover attaching nuts and cover surround-
ing the core pipes.
3.
Remove the glove compartment assembly and the
glove compartment door.
NOTE:.
See "Section 1 - Body" for removal
and installation of body items.
4.
Remove the right kick pad.
5. Remove the right and left center console trim panels.
6. Remove the radio receiver assembly.
7. Remove the defroster duct.
CHEVROLET CHASSIS SERVICE MANUAL

HEATER AND AIR CONDITIONING 1A-73
Fig.
105—Comfortron Control Head
10.
Introduce R-12 vapor at cylinder (room) temperature
and pressure.
11.
Leak test all fittings and connections and give partic-
ular attention to a leak test at the compressor shaft
seal if compressor has not been leak tested on the
bench.
12.
Complete system processing and charge system.
FUSES
A fuse, located in the junction block protects the entire
air conditioning system except for the blower when op-
erating at high speed.
A second fuse, to protect the high speed blower circuit,
is located in the electrical wiring between the horn relay
and the Air Conditioner relay (except Universal). The
Universal unit has a fuse in the line between the ignition
switch and the Air Conditioner blower switch. See the
specification page for the proper replacement fuse.
FOUR SEASON HEATER COMPONENTS
Corvette
The heater components of the system are, in general,
much the same as those of the standard Corvette heater.
Heater hoses carry the engine coolant to the heater core,
located in the air distributor duct beneath the instrument
panel.
A significant difference is that in the Corvette Air
Conditioning System there is no flow through the heater
core until the COOL IN-HOT PULL knob is pulled out.
This movement opens the vacuum switch on the air
distributor assembly and allows vacuum to be applied
to the water valve mounted in the engine compartment,
opening the valve. Thus the heater core is unheated
until needed, at which time it receives full flow of the
engine coolant. Air passing through the core receives
maximum heat which is tempered by mixing with un-
heated air before entering the passenger compartment.
Heater Core
Replacement
The heater core in the Corvette Air Conditioning
System is removed in the same manner as the core in
the Corvette heater. The distributor assembly must first
be removed from under the dash as covered previously
in this section before the core can be removed and
replaced.
Water Valve
Installation of the water valve is illustrated in Figure
113.
An inoperative valve must be replaced.
Chevrolet
Heater Core
Removal
1.
Disconnect battery ground cable.
2.
Drain radiator
3.
Remove right front fender and skirt assembly.
Fig.
106—Comfortron Temperature Dial Adjustment
Fig.
107—Amplifier Removal
CHEVROLET CHASSIS SERVICE MANUAL

HEATER AND AIR CONDITIONING 1A-74
Fig.
108—Comfortron Power Servo Installation
4.
Disconnect heater' hoses from heater core (at
firewall).
5. Remove glove box door.
6. Remove glove box interior.
7. Disconnect right, left, and center air conditioning
outlet hoses from distributor duct.
8. Remove air distributor duct from heater
housing.
9. Disconnect hose and cable clamps from heater
housing.
10.
Remove the remaining three heater housing stud
retaining nuts (engine compartment) and one upper
retaining screw (inside vehicle).
11.
Pull the unit away from the firewall and out of the
car.
ADJUSTMENT
SCREW
Fig.
109—Mode Shift Vacuum Diaphragm
Fig. 110'—Compressor Mount—L-6 Engines (Typical)
12.
Remove heater.housing cover from heater housing.
13.
Remove heater core from heater housing cover by
removing four (4) retaining screws and two "U"
clamps.
14.
Remove heater core.
Installation
1.
Replace core in case using a non hardening sealer.
Attach the core clamps and retaining screws.
2.
Attach the heater housing cover to the housing.
3.
Position the unit against the firewall and attach
it with the retaining screw at the top of the case.
4.
Attach the sheet metal nuts to the case studs which
project through the firewall to the engine side.
5. Connect the control cables to the control doors and
case.
6. Attach the air distributor duct to the case.
7. Connect the left, right, and center outlet hoses.
8. Replace the glove box assembly.
9. Connect heater hoses to core tubes.
10.
Replace fender assembly.
11.
Fill cooling system and connect battery cable.
Camaro
Lower Heater Hose
Removal
1.
Drain radiator.
2.
Remove side mouldings and retainers.
3.
Remove lower fender attaching bolts.
4.
Remove skirt to fender and skirt to reinforcement
bolts.
5. pry the skirt away from the fender flange and away
from the firewall. Block the skirt (four inchlengtti
of 2 x 4) clear of the lower hose and proceed with
the hose replacement.
Installation
1.
Connect the hose.
2.
Remove the block, move the skirt into position and
install all attaching bolts.
3.
Replace fender attaching bolts and mouldings.
4.
Refill cooling system.
CHEVROLET CHASSIS SERVICE MANUAL

HEATER AND AIR CONDITIONING 1A-76
Fig.
112—-Heater Core Removal—Four-Season System (Corvette)
3.
Replace the core case into the car as described
under Heater and Air Distributor Assembly.
COMPRESSOR
The same basic six.cylinder reciprocating compressor
is used in all systems.
Two variations of the basic compressor are used. One,
with a displacement of 12.6 cu. in. is used with the Four-
Season System. The second model, having displacement
of 10.8 cu. in. is used with the Universal and All-Weather
Systems.
AH Systems
Removal
1.
Purge the refrigerant from the system.
2.
Remove connector attaching bolt and connector. Seal
connector outlets.
3.
Disconnect electrical lead to clutch actuating coil.
4.
Loosen brace and pivot bolts and detach belt.
5. Remove the nuts and bolts attaching the compressor
brackets to the mounting bracket.
6. Before beginning any compressor disassembly, drain
and measure oil in the compressor. Check for
evidence of contamination to ..determine if remainder
of system requires servicing. Compressor Servicing
information is located in the Chassis Overhaul
Manual.
Installation
1.
li oil previously drained from the compressor upon
removal shows no evidence of contamination, replace
a like amount of fresh refrigeration oil into the com-
pressor before reinstallatLon. If it was necessary to
service the entire system because of excessive con-
tamination in the oil removed, install a full charge of
"fresh refrigeration oil in the compressor. (See
Checking Compressor Oil Charge under Checking
Oil)
2.
Position compressor on the mounting bracket and
install all nuts, bolts and lock washers.
3.
Install the connector assembly to the compressor
rear head, using new "O" rings.
4.
Connect the electrical lead to the coil and install
and adjust compressor belt.
5. Evacuate and charge the system.
6. Leak test the system and check for proper operation.
Fig.
113—Heater Hoses^-Four-Season System (Corvette)
CHEVROLET CHASSIS SERVICE MANUAL

HEATER AND AIR CONDITIONING 1A-82
•BATTERY
(POS)
CABLE
NOTE
When
control
switch*
is !TOFF"
&
Air
Cond
is
"ON"
(Control
knob
pulled
but) the
blower
fan'will
run at low
speed.
CONTROL
SWITCH
CONNECTIONS
OFF
LOW
MED
HIGH
B
TO
NONE
B
TO L
BTOL&M
B
TO L
&
H
COMPRESSOR
GROUND
WIRE
ASM
BATTERY
(NEGATIVE)
CABLE
COMPRESSOR
ASM
DASHPAJSTEL
GROMMET
16DG
CONTROL
SWITCH
RESISTOR
ASM
14LBL
14BRN
CLUTCH
COIL
EXTENSION
WIRE
ASM
-14BRN--N
JUNC
BLOCKi
OSTATIC
SWITCH
CONTACTS
NORMALLY
CLOSED
STARTING
MOTOR
SOLENOID
BLOWER
MOTOR
AIR
COND
CONTROL
(PUSH-PULL)
KNOB
DOOR
SWITCH
(PUSH
BUTTON
NORMALLY
CLOSED)
RELAY
ASM
HORN
RELAY
DIVERTER
DOOR CABLE
FUSE
PANEL
EVAPORATOR
ASM
IGNITION SWITCH-
ACCESSORY TERMINAL)
Fig. 118—All Weather Wiring Diagram (Chevy II)
CHEVROLET CHASSIS SERVICE MANUAL

HEATER
AND AIR
CONDITIONING
1A-84
SPECIAL TOOLS
18
19 20 21 23 24
28
30
32
Fig.
120—Air Conditioning—Special Tools
1.
1A.
IB.
2.
3.
4.
5.
6.
7.
00*
9.
10.
11.
12.
13.
14.
15.
J-8393
J-22368
J-21530
J-5453
J-9459
J-5420
J-6084
J-8433
J-9395
J-6272
J-6271
J-7151
J-5421
J-5403
J-6435
J-9396
J-9397
Charging Station
Comfortron System fester
Comfortron Temperature Dial Adjuster
Goggles
90° Gauge Line Adapter
Gauge Line Adapter
Leak Detector
Puller
Puller Pilot
No.
3
Multi-Opener (3-Can)
Fitzall Valve (Single
Can)
Non-Magnetic Clutch Shims
Pocket Thermometers
(2)
#21 Snap Ring Pliers
#26 Snap Ring Pliers
Compressor Holding Fixture
Compressing Fixture
16.
J-9403
17.
J-9399
18.
J-9401
19.
J-9480
20.
J-9392
21.
J-9393
22.
J-9298
23.
J-9481
24.
J-8092
25.
J-9521
26.
J-5139
27.
J-9432
28.
J-9553
29.
J-21508
30.
J-21303
31.
J-9527
,
32.
J-9402
Clutch
Hub
Holding Tool
9/16" Thin Wall Socket
Hub
and
Drive Plate Assembly Remover
Hub
and
Drive Plate Assembly Installer
Seal Remover
Seal Seat Remover
Pulley Bearing Remover
Pulley and Bearing installer
Handle
Internal Assembly Support Block
Oil Pickup Tube Remover
Needle Bearing Installer
Seal Seat "O" Ring Remover
Seal Seat "O" Ring Installer
Shaft Seal Protector
Pressure Test Connector
Parts Tray
CHEVROLET CHASSIS SERVICE MANUAL