1967 CHEVROLET CAMARO heater

HEATER
AND AIR
CONDITIONING
1A-31

FIVE
AMP

TIME DELAY

FUSE

CORD
TO

110
AC
SOURCE
PUMP

INLET
PUMP DISCHARGE

OUTLET

Fig.
44—Vacuum Pump

the use of weighing equipment necessary with the larger

drum. The single can Valve J-6271 can be used for com-

pleting the charge and for miscellaneous operations such
Fig.
45-R-12 Disposable Cans

as flushing. The valves are installed by piercing the top

seal of the cans.

Evacuating and charging procedures later in this sec-

tion will make use of the J-8393 Charging Station which

uses the 25 lb. drum of refrigerant.

COMPRESSOR OIL

Special refrigeration lubricant should be used in the

system. It is available in 1 quart graduated bottles

through Parts Stock. This oil is as free from moisture

and contaminants as it is possible to attain by commercial

processes. This condition should be preserved by im-

mediately capping the bottle when not in use.

See "Air Conditioning System Capacities" for the

total system oil capacity.

Due to the porosity of the refrigerant hoses and con-

nections, the system refrigerant level will show a definite

drop after a period of time. Since the compressor oil is

carried throughout the entire system mixed with the

refrigerant a low refrigerant level will cause a dangerous

lack of lubrication. Therefore the refrigerant charge in

the system has a definite tie-in with the amount of oil

found in the compressor and an insufficient charge may

eventually lead to an oil build-up in the evaporator.

COMPRESSOR SERIAL NUMBER

The compressor serial number is located on the serial

number plate on top of the compressor. The serial num-

ber consists of a series of numbers and letters. This

serial number should be referenced on all forms and

correspondence related to the servicing of this part.

INSPECTION AND PERIODIC SERVICE

PRE-DELIVERY INSPECTION

1.
Check that engine exhaust is suitably ventilated.

2.
Check the belt for proper tension.

3.
With controls positioned for operation of the system,

operate the unit for ten minutes at approximately

2000 rpm. Observe the clutch pulley bolt to see that

compressor is operating at the same speed as the
clutch pulley. Any speed variation indicates clutch

slippage.

Before turning off the engine, check the sight glass

to see that the.unit has a sufficient Refrigerant

charge. The glass should be clear, although during

milder weather it may show traces of bubbles. Foam

in.
the flow indicates a low charge. No liquid visible

indicates no charge.

CHEVROLET CHASSIS SERVICE MANUAL

HEATER AND AIR CONDITIONING 1A-32

5.
Check hose clamp connections. If clamp screw torque

is less than 10 lb. in., retighten to 20-25 lb. in. Do

not tighten to new hose specifications or hose leak-

age may occur.

6. If there is evidence of an oil leak, check the com-

pressor to see that the oil charge is satisfactory.

7.
Check the system controls for proper operation.

6000 MILE INSPECTION

1.
Check unit for any indication of a refrigerant leak.

2.
If there is an indication of an oil leak, check the

compressor proper oil charge.

3.
Check sight glass for proper charge of Refrigerant-

12.

4.
Tighten the compressor brace and support bolts and

check the belt tension.

5.
Check hose clamp connections as in step 5 above.

6. Check thermostatic switch setting (Universal and

All-Weather Systems.)

PERIODIC SERVICE

• Inspect condenser regularly to be sure that it is not

plugged with leaves or other foreign material.

Fig.
46—Compressor Connector Block—Typical
• Check evaporator drain tubes regularly for dirt or

restrictions.

• At least once a year, check the system for proper

refrigerant charge and the flexible hoses for brittle-

ness,
wear or leaks.

• Every 6000 miles check sight glass for low refriger-

ant level.

• Check belt tension regularly.

• Every week - during winter months or other periods

when the system is not being operated regularly- run

the system, set for maximum cooling, for 10 or 15

minutes to insure proper lubrication of seals and

moving parts.

INSTALLING GAUGE SET TO CHECK

SYSTEM OPERATION

Compressor Suction and Discharge Connector

Compressor connector assemblies used on all vehicles

are of the same basic design consisting of the inlet

(suction) and outlet (discharge) connections, gauge fittings

and muffler and, in general, the assemblies differ only in

the location of the gauge fittings.

On Universal and Four-Season Systems the outlet line

extends along side of and toward the front of the com-

pressor and the muffler in the line is bracket mounted to

the compressor body. In all Universal Systems the gauge

fittings for both low and high pressure sides of the sys-

tem are located in the connector body. On Four-Season

Systems the high pressure gauge fitting is located on the

muffler and the low pressure gauge fitting is on the POA

Valve.

The Chevy n All-Weather System compressor con-

nector assembly is similar to the Universal System

connector assembly described above except that the

muffler extends straight out from the connector and

is not bracket mounted to the compressor.

Universal and Chevy II All-Weather System

1.
Install Gauge Adapter (J-5420 or J-9459) onto the

high and low pressure hoses of the gauge set.

2.
With the engine stopped, remove the caps from the

cored valve gauge, connectors on the compressor

fittings block.

3.
Connect the gauge lines with adapters to the threaded

connectors on the compressor fittings block.

Four-Season and Comfortron Systems

Installation of the gauge set onto the Four-Season and

Comfortron systems is accomplished in the same manner

as outlined above except that system performance checks

must be performed with the low pressure hose line and

adapter attached to the fitting on the POA valve. Charging

procedures should be performed with the high pressure

gauge line connected to the high pressure gauge fitting

located on the outlet line muffler and the low pressure

gauge line attached to the POA fitting.

CAUTION: When removing gauge lines from

the compressor fittings block be sure to remove

the adapters from the fittings rather than the

gauge lines from the adapters.

PERFORMANCE TEST

This test may be conducted to determine if the system

is performing in a satisfactory manner and should be

used as a guide by the serviceman in diagnosing trouble

CHEVROLET CHASSIS SERVICE MANUAL

HEATER AND AIR CONDITIONING 1A-33

within the system. The following fixed conditions must be

adhered to in order to make it possible to compare the

performance of the system being tested with the stan-

dards below:

1.
Doors and windows closed. (Car inside or in shade.)

2.
Hood up and engine exhaust suitably ventilated.

3.
Vehicle in NEUTRAL with engine running at 2000

rpm.

4.
Air Conditioning controls set for -

• Maximum cooling.

• High blower speed.

5.
TEMP knob and AIR knob set for full recirculating

air. On Comfortron systems* move the control lever

to REAR and pull the white vacuum hose from the

transducer. Plug the hose. An alternate method is to

install the J-22368 Tester (described later in this

section) and operate it on MANUAL control to main-

tain maximum cooling and blower speed.

6. Gauge set installed.

7.
System settled out (run-in approximately
10
minutes).

8. A thermometer placed in front of vehicle grille and

another in the right hand diffuser outlet.

PERFORMANCE DATA

The following Performance Data define normal opera-

tion of the system under the above conditions. Relative

humidity does not appear in the tables because after

running the prescribed length of time on recirculated air

and maximum cooling, the relative humidity of the air

passing over the evaporator core will remain at ap-

proximately 35% to 40% regardless of the ambient

temperature or humidity.

Should excessive head pressures be encountered at

higher ambient temperatures, an 18" fan placed in front

of the vehicle and blowing into the condenser will provide

the extra circulation of air needed to bring the pressures

to within the limits specified.

NOTE: Higher temperatures and pressures will

occur at higher ambient temperatures, fti areas

of high humidity it is possible to have ther-

mometer and gauge readings approach but not

reach the figures listed in the performance

tables and still have a satisfactory operating

unit. However, it is important to remember that

low pressure has a direct relationship to nozzle

outlet temperature. If pressure is too low, ice

will gradually form on the evaporator fins, re-

stricting airflow into the passenger area and

resulting in insufficient or no cooling.

Four-Season and Comfortron System

Chevrolet and Camaro
Chevelle

(Refrigerant
Charge
=

Temperature
of Air

Entering Condenser

Engine rpm

Compressor

Head Pressure

Evaporator Pressure

at POA

Discharge Air Temp,

at Right Hand Outlet
3
Lbs. -

70°

145-

155

38-

41
80°

170-

180
12 02

90°
.)

100°

2000

205-

215

29.5 -

39-

42
41-

43
255-

265

30.5

42-

45
110°

260-

270

psi

43-

46
120°

295-

305

45-

48
(Refrigerant Charge =

Temperature of

Air Entering

Condenser

Engine rpm

Compressor Head

Pressure

Evaporator
Pressure

at
POA

Discharge Air

Temp, at Right

Hand Outlet
3 Lbs. -

70°

150

160

37-

40
80°

175

185
12 Oz.)

90° 100°

2000

210 250

220 260

29.5 - 30.5

37-

40
38-
39-

41 42
110°

280

290

psi

40-

44
120°

290

300

41-

45

Corvette

(Refrigerant Charge =

Temp, of Air

Entering Condenser

Engine rpm

Compressor

Head Pressure

Evaporator
Pressure

at
POA

Outlet
Air

Temperature

(at Right
Outlet)
3
Lbs.

70°

150-

170

38-

40
- 4 Oz.)

80°

175-

195

29

38-

40
90°

2000

200-

200
100°

i*pm

240-

260
110°

285-

300

5-
30.5 psi

40-

42
41-

43
43-

45
120°

325-

335

45-

47

Alt Weather System

Chevy II

(Refrigerant
Charge
=

Grille Air

Temperature

Engine rpm

Compressor Head

Pressure

Compressor Suction

Pressure**

Discharge Air Temp,

at R/H Outlet**
2-1/2 Lbs.)

70°

120-

140

13

32-

37
80°

150-

160

14
CO
OO
CO
CO
90°
100°

1500

175-

185

15

35-

40
220-

230

15

36-

41
110°

240-

250

19

37-

42
120°

265-

275

19

38-

43

**When Compressor Clutch Releases

COMFORTRON SYSTEM OPERATIONAL TEST

This test, designed as a quick check of total system

operation, must be made with the engine operating at

minimum of 2000 rpm and coolant warm. Wait several

seconds between operations to allow the system to move

through its sequence of operation and arrive at the pre-

scribed mode of operation.

1.
With control lever in the OFF position, and Tem-

perature Dial at 65°F.

a. System is turned OFF, there is no air flow from

any of outlets.

2.
Control lever in HI Front and Temperature Dial set

at65°F.

CHEVROLET CHASSIS SERVICE MANUAL

HEATER AND AIR CONDITIONING 1A-34

a. Blower comes on High speed.

b.
Cold air comes from A/C outlets.

3.
Rotate Temperature Dial to 85°F.

a. Blower speed will decrease to Low speed then

increase to Medium or High.

b.
Air temperature changes from Cold to Hot and

comes out heater outlet.

4.
Move control lever to LOW Front, with Temperature

Dial at 85°F. Blower operates at Low and Medium

speeds.

5.
Move control lever to Rear, set Temperature Dial

at 65°F.

a. Blower goes to High speed and maintains high

air flow.

b.
All air comes from A/C outlets.

6. Move control lever to DE-FOG.

a. Blower is on Medium or High Speeds.

b.
Air comes from Defroster and Heater Outlets.

7.
Move control lever to DE-ICE.

a. Blower is on High Speed.

b.
Air temperature goes to warm and most of air

comes from defroster nozzle, with small amount

of air coming from heater outlet.

c. Outside air door is open - (door valve is closed

to car body).

8. Move control lever to REAR (dial at 65°). Outside

air door moves outboard. (Door valve is open to

car body).

CHEVROLET COMFORTRON TESTER

The J-22368 Automatic Temperature Control Tester

when in AUTOMATIC position, may be used to perform
Comfortron system checks without disturbing normal car

operation.

Under MANUAL control tester allows the operator to

set and hold a predetermined blower speed
and.
temper-

ature. The tester can also be used to measure external

system voltages by using the probe.

To Install the Tester

1.
Remove the three-terminal male connector from the

Amplifier on the Comfortron control head.

2.
Plug this connector into the three terminal female

connector (with yellow wire)
on
the Tester.

3.
Plug the remaining three-terminal male connector

on the Tester into the Amplifier on the control head.

4.
Attach the black ground lead to any good ground

point available in the car.

5.
Remove the large vacuum hose from Transducer and

connect it to the Tester vacuum hose nipple.

6. Connect the Tester vacuum hose (short hose) to the

Transducer.

Quick Test Procedure

With the J-22368 Tester installed as outlined above,

the following quick checks may be made to pinpoint

the cause of system malfunctions. This quick check

procedure is reproduced on the "swing out" plastic

instruction card attached to the back of the Tester.

Before performing the checking procedure, start the

engine and allow to run on fast idle until operating

temperature is reached. Then set the dash control lever

to HI-FRONT position and the dash control Temperature

Dial to 75° and proceed with the following steps:

Step

1

2

3

4

5A

5B
Tester Settings

Rocker

Switch

Manual

Manual.

Manual

Manual

Manual

Auto-

matic
Voltage

Source

Sensor

Amplifier

or

Control

Cal.

Trans-

ducer

Amplifier

or

Control

Cal.

Amplifier

or

Control

Cal.
Manual

Control

150

150

a. Max.

Heat*

b.
Max.

Cold*

a. Max.

Cold*

b.
Max.

Heat*

Set to

150 for

Comfortron

System

Same as 5A.

Allow 5 min.

for system

to stabilize

with doors

and windows

closed.
Tester Should

Indicate:

Battery Voltage

Battery Voltage

0-4 Volts

8 Volts Min.

8 Volts Min.

0-3 in. Vac.

0-4 Volts

9 in. Min. Vac.

6.5 Volts

5.5 to 7.5 Volts
To Correct Abnormal Indication:

Check fuse and wiring.

Check for open in sensor circuit.

See Service Manual:

Malfunctioning Amplifier or Temperature

Dial.

Check for open or bad ground in trans-

ducer circuit or replace transducer.

Rotate car temperature dial until meter

reads 6.5 volts. Car temperature should

'•- indicate 75°. If not, see temperature

calibration which follows.

After 5 minutes of operation check for

defective sensor.

•This setting should result in HIGH blower speed. Refer to shop manual for further operational checks.

CHEVROLET CHASSIS SERVICE MANUAL

HEATER AND AIR CONDITIONING 1A-35

Checking Condition of Thermistors (Sensors)

1.
Install Tester J-22368 as previously described.

2.
Start the engine and run at fast idle. Move the

Comfortron control lever to HI-FRONT.

•Set Rocker switch to MANUAL.

•Set Manual Control Knob to 150 ohms on scale.

3.
Set the Tester Voltage switch to AMPLIFIER.

4.
Rotate Comfortron Temperature dial until the Tester

voltmeter reads 6.5 volts. The dial should read 75°,

Adjust dial if necessary.

5.
After car has run (windows and doors closed) for at

least 10 minutes, switch Rocker switch to AUTO-

MATIC. Voltage reading should remain at 6.5. A

change in the voltage indicates a bad sensor.

6. If a bad sensor is indicated in Step 5, check each

sensor, disconnected from the system, with an ohm-

meter. Approximate resistance of each sensor at

75°F.
should be as follows:

In-car Sensor — 50-75 ohms

Ambient Sensor --,55 ohms or less

Duct Delay Sensor -.- 25-75 ohms

Feedback

Potentiometer —

Master Delay

Thermistor -- 70 ohms

High Blower Delay

Thermistor -- 80 ohms including

10 ohm resistor

(Located in Power Servo casting)
VACUUM
ELECTRICAL LEAD

GROUND

LEAD

Fig.
47—Comfortron System Tester x

COMPLETE SYSTEM CHECKS

The following information should be used whenever

preliminary checks indicate the need for further, more

specific, tests. Together with the Electrical Test Dia-

gram (fig. 49) and the Vacuum Diagram (fig. 50),

they may be used to accurately pinpoint any malfunction

of the system.

Fig.
48—Comfortron Tester Installation

CHEVROLET OU
SERVICE MANUAL

HEATER AND AIR CONDITIONING 1A-36

(These tests should be performed with the engine at operating temperature.)

SYSTEM CHECKS

Control

Head

Setting

High

Front

Lo

Front

Lo

Front

Hi

Front

Hi

Front
Tester Settings

Function

Manual

Manual

Manual

Manual

De-ice

65° on

Temp.

Dial

Hi

Front

Hi

Front

Hi

Front
Auto-

Matic

1 1

Auto-

matic

Manual

Manual
Manual

Control

Max.

Heat

Rotate

from

Max.

Heat to

Max.

Cold

150

Max.

Cold

Max.

Cold

Max.

Cold

Max.

Heat

Max.

Heat

Max.

Cold
Voltage

Trans-

ducer

Trans-

ducer

Ampli-

fier

Trans-

ducer

Probe

Probe

Trans-

ducer

Trans.
Tester Should

Indicate:

High Blower

Maximum Heat

Reduced Blower

Speed

Complete series of

blower changes from

Hi to Lo to Hi

again.

AMPLIFIE:

Remove conn, from c

Voltage reading she

Short this lead to grc

Voltage reading she

No voltage change in<

COMPRESSOR C

Cooling System

Operation

DE-ICE i

Assuming rest of

system is operating

normally: Max. Heat

1
to windshield.

SENSOR STR

•—

TRAtfSDtfC

0-3"
Vac. Reading

8 Volts Min.

9"
Min.
Vac.
Reading

0-4 Voltage Reading
If not, check

the following:

Fuse in Slock

In Line Fuse

High Blower

Delay Relay

Duct Delay

Thermistor

High Blower

Delay Sensor

Power Servo

Blower Switch

Resistor

Blower Motor

Wiring Harness

Blower Switch

Master Delay

Thermistor

Master Delay

Relay

Resistor

Power Servo

Blower Motor

CHECK

Resistor

I CHECK
Electrical Diagram

Probe Points:

1-2

8-9

10-21

20

18

19

*
9-46

-r

^2-3
15

16

Checked during

above procedure.

(This is a com-

plete step-by-step

high blower circuit

check which also

checks wiring

harness.)

4

5

6

L2-13

L4

""§2-15

39-46

1
16 1

14

22-40-42-44-15

.ontrol head temperature dial.

>uld be 9 volts minimum,

jund.

>uld be 0 volts,

iicates malfunctioning of amplifier.

JUTCJH CHUCK

Compressor Clutch

(Grille Temp, must

be above 40°.)

IRCUIT

Blower Switch

Master Delay

Relay

Transd

NGCl
ucer

Sensor String

2R CHECK

Transducer voltage

&t Max. Cold

position)

Transducer Ground

Hi Blower Outside

air (air door closed

to car body). Hot air

from heater outlets.

Hi Blower Recirc.

Air (air door open

to car body) cold air

from A/C outlets.
24-25-26-27-28
Voltmete

should re
ad

Battery Voltage

Battery Voltage

Battery Voltage

. Vtinimum
6
volts

Battery Voltage

Minimum
6
volts

Battery Vo]

Batterv Vo]
Ltage

Ltage

Battery Voltage

Batterv Voltage

3a

Bai
:terv Vo

tterv Vo
tage

tage

Minimum
6
volts

Batterv Voltage

Minimum
6
volts

Battery Voltage

Minimum
8
volts

Minimum 8 volts

Minimum 8 volts

Batterv Voltage

Minimum 8 volts

1 III • II »ll. —..• —•— . !!•• 1

Battery Voltage

3-23

20-10-21

38

29-30-31-32-33-

34-35-36

37-38

Defective Power Servo; Leak in Vacuum

System; Temp.; Door Link Disconnected

or Jammed; Defective Vacuum Relay

Valve

Defective Mode Door Diaphragm
Batterv Voltage

Battery Voltage

Zero Voltage

Battery Voltage

Battery Voltage

CHEVROLET CHASSIS SERVICE MANUAL

HEATER AND AIR CONDITIONING 1A-37

VACUUM SYSTEM COMPONENT FUNCTION

Component

Air Door Diaphragm

Power Servo

Vacuum Relay Valve

Mode Door Diaphragm

Defroster Diaphragm

Transducer

Thermo Vacuum Valve
Vacuum Applied

Air Door Open to Outside Air

(Closed to Car Body)

Maximum Heat

Vacuum Applied to One Port Opens a Passage

Through the Valve to Allow Transducer Vacuum

to be Supplied to the Power Servo

Vacuum to Linkage Side

Air Flow Out Heater

Ducts

Full Airflow Out Heater

Outlet
Vacuum to Covered Side

Airflow Out of Upper

Outlets

Full Airflow Out Defroster

Outlets (Full De-ice)
No Vacuum Applied

Air Door Open to

Re circulated Air

(Open to Car Body)

Maximum Cooling

No Vacuum Applied Closes

Vacuum Supply to Power

Servo

Airflow Out of Upper and

Lower Outlets Door Open

1"
from 100% Lower Out-

let Position

Airflow Divided 1/3 Out

Defroster Outlets 2/3

Out Heater Outlets

Supplies Modulated Vacuum to Power Servo

Zero Voltage Applied to Transducer

Results in Maximum Vacuum Supply
10 Volts Applied to Transducer

Results in No Vacuum Supply

(Coolant Hot) Passes Vacuum When System is Calling For Outside Air

MAINTENANCE AND ADJUSTMENTS

EVAPORATOR CONTROL VALVE (POA)

(Chevrolet, Chevelle, Comoro, and Corvette

Four Season) (Chevrolet Comfortron)

The only check for proper POA valve operation is to

check the suction pressure at the valve as during a

performance test. The POA valve is an absolute valve

and will provide different gauge readings based on the

altitude where the readings are being taken. Correct

gauge reading at sea level is 29.5 psig. Gauge readings

will be one-half psi higher for each additional 1000 feet

of elevation. The following table lists gauge readings at

different altitudes. If a valve gives improper gauge

readings, it must be replaced since it is not repairable

or adjustable.

29.5

30.0

30.5

31.0

31.5

32.0

32.5

33.0

33.5

34.0

34.5
psig.

psig.

psig.

psig.

psig.

psig.

psig.

psig.

psig.

psig.

psig.
— Sea 1

— 1000

— 2000

— 3000

— 4000

— 5000

— 6000

— 7000

— 8000

— 9000
Level

ft.

ft.

ft.

ft.

ft.

ft.

ft.

ft.

ft.

— 10000 ft.
THERMOSTATIC SWITCH

(Universal and Chevy II All-Weather System)

Thermostatic switches used in Universal and All-

Weather systems differ only in the capillary tube sensing

unit.

The Chevy n All-Weather System thermostatic switch

has an air sensing capillary which is coiled and attached

to the front of the evaporator core with plastic plugs.

This type of unit is controlled by the temperature of the

air leaving the evaporator.

Universal systems make use of a thermostatic switch

with a fin sensing capillary or a self-supporting air sens-

ing capillary. This capillary controls the switch by

sensing the temperature of the metal fins or the air

leaving the fins.

Checking for Proper Operation

1.
Install the gauge set and set up the vehicle as

described under Performance Test.

2.
Movement of the temperature control knob should

result in a definite change in suction pressure and

cycling of the compressor clutch.

• If compressor continues to operate regardless of

the knob adjustment, it indicates that the points

CHEVROLET CHASSIS SERVICE MANUAL

HEATER AND AIR CONDITIONING 1A-38

HIGH BLOWER

DELAY RELAY

O) MASTER AND

HIGH BLOWER

DELAY RELAY

GROUND

Fig.
49A-Comfortron Wiring Diagram-Underhood

CHEVROLET CHASSIS SERVICE AAANUAL