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
HEATER AND AIR CONDITIONING 1A-68
Fig.
95—Corvette Four-Season Ducts
5. Connect the various Comfortron harness connectors
to the dash wiring and connect the vacuum hose to
the kick pad valve diaphragm. Push the vacuum hose
harness and wiring harness through the firewall to
the proper location and install their respective
grommets.
6. Raise the control unit into place and install the
mounting screws. Check that all connections are
complete.
7. Replace any radio and/or tape equipment, the ash
tray assembly, and face plate.
8. Replace the glove box assembly.
9. Connect the heater hoses to the core tubes, and
attach the nuts to the case studs through the firewall.
10.
Reconnect the four vacuum hoses as follows: Purple
to the cylinder on the thermo-vacuum valve, yellow
tracer to the body of the thermo-vacuum valve, red
tracer to the vacuum source "Tee" connection, and
white tracer to the vacuum tank inlet.
11.
Connect the wiring harness to the underhood air
conditioning components.
12.
Refill cooling system, connect battery ground cable
and check system performance.
Vacuum Tank
The vacuum tank is mounted on the firewall as shown
in Figure 97. Notice that the two vacuum lines are
clamped to the vacuum tank ports. *
Thermal Vacuum Valve
This heat operated vacuum valve is located in the
heater core input line. Figure 98 illustrates valve instal-
lation with clamps attaching the water hoses as well as
the vacuum hoses in place.
Resistor Assembly
Figure 99 illustrates the location and installation of
the blower speed resistor assembly.
Relays
Two relays are used in the system, both mounted on the
evaporator case as shown in Figure 100. The mounting
bracket forms a common ground for the relays and as a
plug for the hole in the evaporator housing used in the
Four Season system for resistor installation.
Sensors (Thermistors)
Ambient Switch and Sensor
This combination unit, which engages the compressor
clutch at about 40°F and also senses outside air tem-
perature and sun load, is mounted to the firewall within
the engine compartment with its long neck extending
deep into the cowl vent plenum chamber. Figure 98 il-
lustrates this installation,
In-Car Sensor
This sensor is located beneath the lip of the instru-
ment panel overhand just to the right of the driver as
shown in Figure 101.
Removal
1.
Remove glove box assembly.
2.
Disconnect sensor wires connector at harness.
3.
Remove sensor mounting screws, remove sensor
and pull wires and connector through hole in dash.
Installation
1.
Insert connector and
through the dash hole.
wires of replacement sensor
CHEVROLET CHASSIS SERVICE MANUAL
HEATER AND AIR CONDITIONING 1A-70
Fig.
98—Comfortron Thermal Vacuum Valve
Power Servo .
The Power Servo is attached, to the distributor duct.
The entire installation consists of the Servo Assembly
and its link assembly to the TEMP door. The Servo is
attached to the Air Selector Duct as shown in Figure 108.
Mode Shift Vacuum Diaphragm
Replacement
1.
Remove the heater distributor from the vehicle.
2.
Reach into the distributor through the AIR door
opening to reach and remove the vacuum diaphragm
mounting screws and diaphragm to door link screw
(remove piug from case to reach this screw).
3.
Reverse this procedure to replace.
4.
Adjust mode door without vacuum applied to dia-
phragm. The door should be open one inch from
sealing against the air distributor opening (inside of
case).
(Figure 109).
HIGH BLOWER
DELAY RELAY
.MASTER
DELAY
RELAY
Fig.
100—Comfortron Relays
COLLISION PROCEDURE-AII Systems
Whenever a car equipped with air conditioning unit is
involed in a collision or wreck, it should be inspected as
soon as possible. The extent of damage to any or all of
the component parts and the length of time the system
has been exposed to the atmosphere will determine the
replacement of parts and processing that will be re-
quired. The greater the length of time of exposure to the
atmosphere, the greater will have been the chances for
air, moisture and dirt to have entered and damaged the
system. Every case may be entirely different so it is not
possible to establish a hard and fast procedure to follow
each time. Good judgment must be used to determine
what steps should be taken in each specific case.
The following procedure is presented as a guide for
Fig.
99—Comfortron Resistor Assembly
Fig.
101—Comfortron Sensor Installation
CHEVROLET CHASSIS SERVICE MANUAL
HEATER AND AIR CONDITIONING 1A-71
SUN-AMBIENT
SENSOR AND COMPRESSOR
CLUTCH SWITCH
HIGH BLOWER
DELAY RELAY
THERMAL
VACUUM
VALVE
Fig.
102-Comfortron Underhood Wiring
use when inspecting a damaged vehicle equipped with air
conditioning.
1.
Remove the drive belt. Cut belt off if necessary.
2.
Visually inspect the condenser, receiver-dehydrator,
compressor, mounting brackets, conditioning unit, all
connecting lines, and all controls to determine the
extent and nature of the damage.
a. No repairs, such as soldering, welding or braz-
ing, should be attempted on the condenser be-
cause of its construction. If the vapor passages
in the horizontal tubes or return bends or mani-
folds have been damaged in any way, the con-
denser should be replaced with a new one.
b.
The receiver-dehydrator should be replaced if
there is any evidence of its having sustained
either internal damage or a fracture at any of
the lines or welded joints or if the system has
been exposed to the atmosphere for an undeter-
mined period of time.
c. Examine the compressor for any visible external
damage.
d. The evaporator should be examined for damage
and, if necessary, removed or replaced or the
entire unit processed where damaged or exposed
to the atmosphere.
e. All connecting lines and flexible hoses should be
examined throughout their entire length for dam-
age.
If damaged in any manner, replace with new
lines.
f. Check all controls and connecting wires for
damage and replace with new parts where needed.
g. Check the clutch pulley for proper operation and
freedom from damage.
3.
Install gauge set.
4.
Purge the system. Pressure should not exceed 3 to
5 pounds.
5. Remove the compressor from mounting and remove
the oil test fitting.
6. Pour out the oil into a clean glass container and ex-
amine it for any foreign substance such as dirt,
water, metal particles, etc. If any of these are
present, the compressor and receiver-dehydrator
should be replaced and the other system components
should be flushed with liquid refrigerant.
7. If the oil is clean and free of any harmful substance,
replace oil with Frigidaire Oil available through
Parts Stock.
NOTE:
If the system components have been
replaced or flushed, replace the full charge of
oil. If not, add no more fresh oil than was
drained in Step 6.
8. Charge up the compressor to drum or can pressure
and leak test the compressor seals prior to in-
stallation of compressor.
9. Reinstall the compressor and evacuate the system
by following the Evacuating Procedure.
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-78
WIRING DIAGRAMS
Blower
Motor
Resistor
•
Asm
EVAPORATOR—v
ASM.
\
-Diode
(Arc I
suppressor)
^\
16B
—>
-COMPRESSOR
Clutch Coil
•To battery positive
(+) terminal
No vacuum
in hose
#3
Blower
intake
air
Outside
air entry
Valve
by vacuum
in
hose
#3
Valve
normally
closed (spring
held)
Inside
car
air
(Recirc.)
AIR INLET
VALVE
POSITION:
Outside
air
intake
Recirc. air'intake
CONTROL ASM
TEMP CONTROL LEVER
(Operates temp valve
cable
&
equipment
in
chart shown below)
Compressor
Sw.
(Normally closed
Temp valve
begins
to
open
valveV
cable
arm
•Fan Speed Selector Switch
Switch
lever
position
Off
Low
Med
High
Contacts
made
B
to
None
BtoL
B to L
&
M
B to
L
& H
Fan
speed
Low
Low
Med
High
Resistance
in series with
Bio Motor
Hi
Rl
(RiR2)/(Rl+R2)
None
•Blower switch contacts must
be
dosed
before
fan
switch will
be
operable.
COLD
(O.
A.)
COLD a.A.)
Blower
H
y—low
switch
M/
-med
(Norm,
closed
contacts)
Fan speed switch
(See chart
at
left)
To vacuum,
tank
EXTENSION—vy
Horn relay "Bat" WIRE
ASM
X
harness
terminal
V
.**-__.. ;_
1 I panel
Legend:
___. —
Production wiring
Wire
is
part
of
equip.
•—————* Air
conditioning
wrg.
| i
T Agn. sw.
accsy
I term.
I
Temp
Control
Lever
Position
OFF
VENT.
COLD(I.A.)
COLEKO.AJ
HOT
Blower
(Master)
switch
contacts
Open
Closed
Closed
Closed
Closed
Vac switch
connects
vac source
to hose
#
#2
#2
&
#3
None
#3
#2
&
#3
Compressor
switch
contacts:
Open
Open
Closed
Closed
Open
Blower
intake
air
Outside
car air
intake used
Inside
car air
recirculated
Outside
car air
intake used
.Outside
car air
intake used
Fig. 114—Chevrolet—Four-Season Wiring Diagram
CHEVROLET CHASSIS SERVICE MANUAL
HEATER
AND AIR CONDITIONING IA-79
BAT.
CABLE
ASM
A/C
wrg fwd of
dash
exc
bat.
cables,
ext
wire
&
compressor
grd
wire
is
part
of engine wiring harness.
"COMPRESSOR"
SW:
"OFF" POSN
"ON"
POSN
RELAY
ASM
/-DASH
/
PANEL
RESISTOR
ASM
LUTCH
COIL
:OMI
GRD
WIRE
ASM
MPRESSOR
BAT.
TERM
ON START
MTR SOL
EXTENSION WIRE ASM
._
J
J
^-CONTROL
SW
CONTACTS
B TO NONE
BTOL
BTOL&M
BTOL6H
•IGN SW ACCSY TERM.
A/C wrg
to
rear
of
dash
of
inst pnl harness.
Fig.
115—CheveIle—Four-Season Wiring Diagram
CHEVROLET
CHASSIS SERVICE MANUAL
HEATER
AND AIR
CONDITIONING
1A-80
EVAPORATOR ASM.
Blower
Motor
INSIDE VALVE
(Normally closed
-spring held)
PLENUM VALVE
(Normally open
-spring held)
Actuator
(Vacuum
operated)
Inside car air (Recirc*
CONTROL ASM
TEMP CONTROL LEVER
•(Operates temp valve
cable
&
equipment in
hart shown below)
Temp valve
begins to
16DG
Fuse (In-line^
COMPRESSOR
Clutch Coil DASH-
PANEL
•Fan Speed Selector Switch
Switch
lever
position
Off
Low
"HeST
High
Contacts
B to
None
BtoL
B to L b U
BtoL&H
Fan
speed
Low
Low
Med
High
Resistance
in series with
Bio Motor
Rl
Rl
RlR2)/(Rl+R2)
None
•Blower switch contacts must be closed
before fan switch will be operable.
-To battery positive
(-0 terminal
•
Horn relay
terminal"
"Batf
To vacuum
tank
EXTENSION
WIRE
ASM
(Normally closed
contacts-*vac
operated)
7
*- Fan speed switch
(See chart at left)
•/-Wire is
\ part of
I inst panel
harness
Legend:
— Production wiring
————
Wire Is part of equip.
•mmmmmmmmmmmmmm*
AIT
Conditioning
WTg*
Temp
Control
Lever
Position
OFF
VENT
COLD
a.A.)
COLD
(O.A.)
HOT
Blower
(Master)
switch
contacts
Open
Closed
Closed
Closed
Closed
Vac switch
connects
vac source
to hose #
#2
&
#3
#2
#3
None
#2
Compressor
switch
contacts^
Open
Open
Closed
Closed
Open
Blower
intake air
Outside car air
intake used
Inside car air
recir culated
Outside car air
intake used
Outside car air
intake used
Fig.
116—Camaro—Four-Season Wiring Diagram
CHEVROLET CHASSIS SERVICE