1967 CHEVROLET CAMARO electrical

GENERAL INFORMATION 0-7

a vise using leather or wood on each side to prevent

damage to the cylinder,

7. Stake the retainer securely in place by staking the

cylinder metal over both edges of the retainer ends

using a suitable staking tool at right angles to the

top of the retainer and from the cast metal of the

cylinder over the retainer at each corner.

PUSHING, TOWING AND LIFTING

Pushing

NOTE:
Towing car to start is not recommended

due to the possibility of the disabled car ac-

celerating into tow car.

AUTOMATIC TRANSMISSION

Do not attempt to start the engine by pushing the car.

Should the battery become discharged, it will be neces-

sary to use an auxiliary battery with jumper cables to

start the engine.

CAUTION: To prevent damage to electrical

system, never connect booster batteries in ex-
cess of 12 volts and connect positive to positive

and negative to negative.

Manual Transmission

When a push start is necessary turn off all electrical

loads such as heater, radio, and if possible, lights, turn

on the key, depress the clutch, and place the shift lever

in high gear. Release the clutch when your speed reaches

10 to 15 miles per hour.

TOWING

The car may be towed safely on its rear wheels with

the (selector lever in "N" (Neutral) position at speeds

of 35 miles per hour or less under most conditions.

However, the drive shaft must be disconnected or the

car towed on its front wheels if 1) Tow speeds in excess

of 35 MPH are necessary, 2) Car must be towed for ex-

tended distances (over 50 miles) or, 3) Transmission is

not operating properly. If car is towed on its front

wheels, the steering wheel should be secured to maintain

a straight ahead position.

DRIVE ON HOIST

BUMPER JACK LIFTING AT FRAME ATTACHMENT ONLY

FLOOR JACK OR HOIST LIFT

Fig.
21-Vehicle Lifting Pointe-Chevroiet

CHEVROLET CHASSIS SERVICE MANUAL

HEATER AND AIR CONDITIONING 1A-4

CHEVROLET SHOWN AS

TYPICAL OF CHEVROLET

AND CHEVELLE

CHEVROLET

WITH CONSOLE

ONLY

THESE USED ON

CHEVROLET ONLY

Fig. 5— Heater Blower and
Air
Inlet (Chevrolet, Chevelle, Camaro)

Core

Replacement

1.
Drain radiator.

2.
Remove the heater hoses at their connections beside

the air inlet assembly.

NOTE:
The hose from the
water,
pump
must go

to the top heater core pipe; the other hose runs

from the thermostat housing to the lower core

pipe. (See Figure 8)

3.
Remove the bowden cables (except the Chevrolet

defroster cable) and all electrical connectors from

the heater and defroster assembly.

4.
On the engine side of the dash, remove the nuts from

the core case studs coming through from the inside

of the car.

5. Inside the vehicle, remove the case to firewall

mounting screws and pull the entire heater and de-

froster assembly from the firewall (remove the
Chevrolet defroster cable at this time) then remove

the assembly from the vehicle and set on a bench.

6. Remove the core assembly retaining springs and

remove the core.

7. Install the replacement core.

NOTE:
Be sure the core to case sealer is

intact before replacing core. Replace with new

sealer if necessary.

8. Replace the core and core retaining springs.

9. Within the vehicle (after attaching the Chevrolet

defroster cable) insert the five studs on the heater

and defroster assembly through the holes in the

cowl and blower and air inlet assembly. Replace the

case to firewall mounting screws and (on the engine

side) the five stud nuts.

10.
Replace the remaining bowden cables and electrical

connectors.

11.
Replace heater hoses, being careful to reinstall

CHEVROLET CHASSIS SERVICE MANUAL

HEATER AND AIR CONDITIONING 1A-5

them in their proper location. (See Figure 8)

12.
Refill radiator.

Defroster Duct

Figure 9 illustrates the defroster duct installation

on Chevrolet, Chevelle and Camaro vehicles.

Bowden Cobles

Bowden cable attachment should be made in the fol-

lowing manner:

1.
With the cables attached to the control assembly

and levers, move the levers to their fully left or

closed position.

2.
Attach cable wires to the heater valve levers and

tighten cable attaching bracket screws.

3.
Check for proper cable operation and readjust as

necessary.

Control Panel

Control panel installation is shown in Figures 10, 11,

and 12.

Fan Switch

Replacement

1.
Remove control assembly-to-instrument panel re-

inforcement attaching screws and push the control

assembly toward the front of the vehicle and down.

2.
Remove the two switch attaching screws and the

electrical connector.

3.
Replace switch, screws, and electrical connector.

4.
Place control assembly into instrument panel and

replace attaching screws.

Resistor

The resistor assembly is attached to the heater dis-

tributor assembly. It should "be replaced if low or

medium blower speed is inoperative. Remove the glove

box for access to the unit.
HEATER HOUSING

LOWER RIGHT HAND

RETAINER NUT

Fig.
6—Air Distributor Duct (Camaro)
Fig.
7—Access to Blower and Housing (Chevelle)

CHEVY II

Heater Assembly

Removal (Fig. 13)

1.
Drain radiator.

2.
From within engine compartment;

a. Remove heater hoses from heater inlet and outlet

connections.

b.
Remove three nuts around blower motor attaching

heater assembly to dash panel.

3.
From within vehicle:

a. Remove glove box and glove box door.

b.
Remove screw attaching distributor bracket to

dash.

c. Remove the screw attaching case bracket to the

adapter assembly bracket.

d. Carefully detach heater assembly from dash panel

and adapter assembly and lower it toward floor of

vehicle.

e. Disconnect all bowden cable connections, the

wiring connector and the defroster hoses.

4.
Remove the heater assembly from the vehicle.

Core Replacement

1.
'With the heater assembly removed from the vehicle,

remove the screws attaching the core cover to the

heater assembly.

2.
Remove the core mounting screws and remove the

core from the assembly.

3.
Replace with a new core and replace the core cover.

Installation

1.
Be sure the adapter seal and blower motor seal are

in place and set into place beneath the instrument

panel.

CHEVROLET CHASSIS SERVICE MANUAL

HEATER AND AIR CONDITIONING 1A-6

CHEVROLET SHOWN AS TYPICAL

Fig.
8—Heater Hose Routing (Chevrolet Shown as Typical)

cables, defroster hoses and the

place and install all at-

4.

5.

6.
Attach all bowden

wiring connector.

Set heater assembly into

taching nuts and screws.

Attach inlet and outlet hoses.

Replace glove box and glove box door.

Refill cooling system.

Defroster Duct

Installation of the defroster duct as used in Chevy H

vehicles is illustrated in Figure 14.

Blower Motor

Replacement

1.
Remove the heater assembly from the firewall.

Remove the five screws attaching the motor and

blower to the heater assembly.

2.
Remove the retainer attaching blower to the motor

shaft.

3.
Replace blower on new motor assembly, balance and

reinstall into heater assembly.

Fan Control

Replacement

1.
Remove the screws at the dash lower edge which

retain the control assembly and lower the assembly.

2.
Disconnect the blower harness connector and remove

the switch retaining screws and switch.

3.
Install the replacement switch with the nylon bearing

inserted into the AIR - FAN lever slot.

4.
Connect the blower harness connector and remount

the control assembly in the dash.
CORVETTE

Blower Assembly

Removal

1.
Remove the radiator supply tank from its retaining

straps and move it out of the way, then disconnect

the battery positive cable.

NOTE:
It is not necessary to drain the radiator.

2.
Remove the connectors from the blower motor.

3.
Scribe or chalk a mark on the blower motor mount-

ing plate and blower assembly.

4.
Remove the five screws retaining the blower mount-

ing plate to the blower inlet assembly.

Withdraw the blower assembly from the inlet

5.

assembly.

Disassembly

Remove the blower wheel from the motor by removing

the nut and tapping the motor shaft with a soft hammer.

Installation

1.
Assemble the blower to motor and using the scribe

mark, properly position the blower assembly on the

inlet assembly and install the five screws.

2.
Replace the electrical connectors on the blower

motor.

3.
Replace the radiator supply tank and the battery

positive cable.

Blower and Air Inlet Assembly

Removal

1.
Drain the radiator.

2.
Remove the radiator supply tank from its retaining

straps and swing it out of the way.

3.
Remove the battery.

CHEVROLET CHASSIS SERVICE MANUAL

HEATER AND AIR CONDITIONING 1A-7

Fig.
10—Control Assembly (Chevrolet)

6. Remove the seven stud nuts attaching the blower

and air inlet assembly to the dash panel.

7.
Remove the blower and air inlet assembly from

beneath the fender.

8. The blower assembly may be removed and dis-

assembled as described under "Blower Assembly"

above.

Installation

1.
With the blower and air inlet assembly in place,

install the seven attaching stud nuts.

2.
Replace the blower motor electrical connectors.

Fig.
9—Defroster Duct (Chevrolet, Chevell^, Camaro)

4.
Disconnect the blower motor electrical connectors.

5.
Remove the water hoses from the heater core inlet

and outlet connections.
\

N

^
1

Fig.
11-Controi Assembly (Chevelle)

CHEVROLET CHASSIS SERVICE MANUAL

HEATER AND AIR CONDITIONING 1A-10

PLATE RETAINERS

CORE BRACKET SCREWS

Fig.
18—Corvette Heater Core Removal

7. Place a protective covering (waterproof if possible)

over the carpeting under the heater.

8. Remove the two bowden cables from the instrument

panel and disconnect the wiring connectors from the

blower switch and from the resistor.

9. Carefully work the heater assembly out from beneath

the dash.

Core Removal

1.
Remove the heater assembly as described above.
2.
Remove the sheet metal nuts which retain the core

mounting plate to the core housing.

3.
Remove the screws attaching the core brackets to

the core mounting plate and separate the core and

plate. .

Installation

1.
Assemble the core to plate with non-hardening

sealer. Attach the core mounting screws.

2.
Attach the core and plate assembly to the case with

the two sheet metal nuts. The assembly is ready for

installation as described below.

Heater Assembly Installation

1.
Carefully position the heater assembly in place on

inner surface of dash panel, then install the blower

and air inlet assembly on heater studs extending

through to the engine side of the panel. Attach the

seven stud nuts.

2.
Install electrical connectors to the blower switch and

resistor and reinstall the bowden cables to the

instrument panel.

3.
Replace the blower electrical connectors.

4.
Replace the heater hoses. (See Figure 20)

5. Replace the battery and the radiator supply tank.

6. Refill the radiator and check for leakage.

7. Check heater operation and make control adjustments

as necessary.

8. Replace the console panels and the glove

compartment.

CHEVROLET CHASSIS SERVICE MANUAL

HEATER AND AIR CONDITIONING 1A-20

and its resistance is decreasing. In the HI FRONT

position, two thermistors (the master delay and high

blower delay thermistors) are warming. The air

door is in recirculation position until the engine

coolant reaches 75 degrees.

2.
The coolant reaches then 75 degrees and the thermal

vacuum valve opens applying vacuum to the air door

to admit outside air (unless the temperature dial is

set for cooling). Ram air will flow through the sys-

tem when the car is moving.

3.
Next, the master delay thermistor attains the tem-

perature at which it will pass sufficient current to

close the circuit through the master delay relay.

The relay circuit powers the blower motor at 9 volts.

4.
If the control is in the HI FRONT position, the high

blower delay thermistor will close the circuit

through the high blower relay which supplies full

available voltage to the blower motor. This function

occurs after the master delay thermistor has taken

effect because the high blower delay thermistor

uses the master delay type thermistor with a 10 ohm

1/4 watt resistor connected in
.
series. The nigh

blower delay thermistor must then warm to a higher

temperature than the master delay thermistor before

its resistance (plus that of the 10 ohm resistor)

drops enough to actuate the high blower relay.

5. If the controls are set for DE ICE, full outside air

and full voltage to the blower motor are effective

immediately regardless of temperatures or elapsed

times o

In accomplishing automatic control, the system follows

three steps to transform an electronic signal into me-

chanical energy through which the control is achieved.

Electronic Circuit

Two temperature sensors (Thermistors), and the duct

potentiometer connected in series, are located so as to

sense the temperature of the outside air, inside air and

system output air. The resistance of each sensor will

vary according to its temperature. The control head

temperature dial varies in resistance as it is adjusted by

the operator to suit his comfort requirements. The

resistance of the temperature dial control is applied

directly to the amplifier and is not in series with the

sensors and duct potentiometer. Thus temperature dif-

ferences in the sensor string plus the requirements fed

into the system by the operator cause changes in total

circuit resistance which allow a varying voltage flow

through the circuit.

Changing the Electronic Signal to Electrical Voltage

This minute voltage flow from the sensor string -

temperature dial circuit - is fed into the amplifier where

it is transformed into a usable amplifier output voltage,

the strength of which is determined by the strength of the

original amplifier input signal. This voltage is then

supplied to the transducer.

Changing the Electrical Voltage to a Vacuum Signal

Amplifier output voltage, varying according to tem-

perature requirements, is converted by the Transducer

into a modulator transducer output vacuum. This modu-

lated vacuum is applied to the Power Servo.

Changing the Vacuum Signal to Mechanical Energy

The Power Servo, controlled by the modulated Trans-
ducer output vacuum, operates the vacuum electrical and

mechanical components of the system as required to

provide automatic control of system operation.

Other major system components are mounted con-

ventionally in the engine compartment. Underhood com-

ponents and system airflow remain much the same as in

the Four-Season system except for the addition of the

automatic control provisions. The system operates on

100%
outside air, a mixture of outside and inside air, or

100%
recirculated air depending on the demands of the

system. The diaphragm operated .air selector door will

modulate outside air to the system during maximum air

conditioning requirements when the control unit is in

"Hi Front" position. Control of the blower is also com-

pletely automatic and dependent upon system demands.

Controls

The Comfortron controls the Chevrolet air conditioner

and heater in such a precise manner that the automobile

temperature remains relatively constant under all driving

conditions. By adjusting the thumb wheel on the Control

Head to any temperature desired between 65° and 85° F.

(See Figure 27) the automatic system will adjust the in-

car temperature even though the outside weather condi-

tions may vary considerably. The system will provide

maximum capacity for heating or cooling until the in-car

temperature reaches the pre-set Control Head Tempera-

ture. Where cooling is required, the system will start

immediately upon being turned "ON". During marginal

ambient temperatures the system will not always start

at the highest blower speeds of the control setting.

Therefore, occasionally the system can't be heard

starting*

Five over-riding functions are available so that special

conditions can be handled. Each Control Head function

will be discussed in detail below:

"Off" Position

In the "Off" position, the blower is turned off and the

outside air door is closed. No outside air should enter

the automobile.

"Lo Front" Position

The blower has five low to moderate speeds; Hi, M3,

M2,
M1 and Lo. The blower voltage will shift as directed

by the automatic controls. The "Lo Front" position

provides a quieter mode of automatic operation due to

reduction of blower noise.

"Hi Front" Position

The "Hi Front" position provides five high blower

speeds as called for by the automatic controls: The use

of the "Hi" blower speed results in a rapid cool down in

hot weather and rapid heating during cold weather. As

the in-car temperature approaches the temperature set-

ting on the Comfortron Control Head, the blower speed

will change, provided mild outside temperatures are

experienced. During very hot or cold weather, the blower

will reduce its speed only to the point where it is still

capable of maintaining the correct inrcar temperature.

"Rear" Position

The "Rear" position provides five high blower speeds.

The automatic controls select these speeds and blend the

discharge air to the proper temperature. By the use of

high blower speeds, increased airflow is obtained for

better rear seat passenger comfort.

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