Opel Frontera UBS. Manual - part 923

1B–86 AIR CONDITIONING

Legend

(1)

Out put Axis

(2)

Motor

(3)

Printed Circuit Board

(4)

Sliding Contact

The mode and mix actuators are common actuators
with the built-in potentiometer. For the intake
actuator, the contact switch type is selected.
The potentiometer is a register assembled to the
printed circuit board of the mix and mode
actuators. It detects the air mix door position
specified by rotation of the output axis as a ratio of
the variable terminal (VM) voltage against the
reference voltage (VDD: 5V), then signals the value
to the automatic heater/air conditioner control unit.

• Movement of Mix Actuator

Position of the air mix door is determined by the
controller on the automatic heater/air conditioner
control unit.
As the heat or cool side of the controller is
grounded, the transistor on the driver is activated
and, thus, the motor rotation is turned on. The
sliding contact connected to the motor sends the
position detection signal from the potentiometer
to the automatic heater/air conditioner control
unit. As the set temperature and interior
temperature are balanced, the controller returns
to the neutral and the motor rotation is stopped.

1

2

4

3

860RW026

C01RX016

M

N

3
2
7

6

8

9 8

4 3

6 5

2 1

7

Potentiometer

Connection

Position

Detection

Block

Automatic Heater / Air

Conditioner Control Unit

Controller

Sliding Contact

Full Heat Position

Terminal Plate

Full Cool Position

Driver

Cool Side

Heat Side

C01RY00016

Full cool

Full cool

0

0

0.5

1.0

50

100%

Aperture of  air mix door

V

oltage r

atio 

VM/VDD

Full heat

Full heat

VDD

VM

+

–

I-45

Rotation

(+) side

(–) side

direction

Remarks

8

6

Clockwise

Full heat side

6

8

Counter

Full cool side

clockwise

AIR CONDITIONING  1B–87

• Movement of Mode Actuator

As target position of the mode door is decided on
the controller of the control unit, the control unit
reads the position detection signal from the
actuator to select the clockwise or counter
clockwise motor rotation direction.
Grounding the controller VENT or DEF side after
the direction selection activates the transistor on
the driver, thus turning on the motor rotation.
Accompanying the motor rotation, the sliding
contact rotates, too. When the target position is
reached, the controller on the control unit returns
to the neutral and the motor stops.

• Movement of Intake Actuator

The controller on the automatic heater/air
conditioner control unit selects an intake mode to
be used.
As the Terminal No.5 

is grounded via the

sliding contact on the terminal plate, the
transistor on the driver is activated, thus turning
on the motor rotation. Then, accompanying
move of the motor, the sliding contact rotates
until grounding of the Terminal No.5 

is

removed, thus stopping the motor.

I-49

I-49

Driver

Controller

DEF side

VENT side

Position

detection

block

Control unit

Sliding
contact

Actuator side
4

2

9 8

3

7

7

8

9

10

H

L

H

L

H

H

H

L

H

H

L

L

H

H

L

H

H

L

L

H

H

L

H

H

L

L

H

H

L

H

H

H

L

H

L

H

6

1
5

Interconnected
motor

VENT

VENT

Mid point between VENT - B/L

B/L

Mid point between B/L - FOOT

FOOT

Mid point between FOOT - D/F

D/F

Mid point between D/F - DEF

DEF

DEF

7

8

9

10

2

6

7

8

3

4

9

5

1

C01RX017

M

+

6

1

2

6 5 4 3

REC

MIX

FRESH

Com

1
2

5

3

4

+

+

—

Terminal Plate

Auto A/C

Control Unit

(Actuator Side)

Driver

Controller

Sliding Contact

Connected

C01RX006

Conducting pin

Rotation

(+) side

(–) side

direction

Remarks

5

1

Clockwise

VENT to

DEF direction

1

5

Counter

DEF to

clockwise

VENT diction

Grounding

Rotation

terminal

direction

Remarks

No.5

Clockwise

RE-CIRCULA

TION

→

MIX

→

FRESH

I-49

1B–88 AIR CONDITIONING

OVERVIEW OF AUTOMATIC CONTROL OF
FULL AUTOMATIC AIR CONDITIONER 

The full automatic heater and air conditioner on this
vehicle has the following features:

• Interior temperature control.

• Air flow control.

• Mode (blow port) control.

• Intake (switching between fresh air and interior

air) control.

• Heater start timing control.

• Cooler start timing control.

• Evaporator anti-freeze control.

1. Interior Temperature Control

The automatic heater/air conditioner control unit
operates on the setup temperature signal from
the temperature control switch and other sensor
signals to derive the total signal. Then, the
control unit compares this signal against the
signal from the potentiometer to determine
rotation direction of the mix actuator. The mix
actuator moves the air mix door to the aperture
specified by the total signal so that the specified
interior temperature is achieved.
If the compressor is turned off in the A/C (air
conditioning) mode, aperture of the air mix door
is offset according to the outside air temperature
or the specified interior temperature. This
function removes the difference in the blowing
temperature in this state and that of when the
compressor is turned on.
When FH or FC is selected for the setup
temperature, the air mix door is accordingly
fixed to the Full Heat or Full Cool mode.
When the VENT mode is selected, aperture of
the air mix door is controlled so that excessively
heated air may not be blown from the VENT
blow port.

0

50

140

104

68

32

Air mix door aperture

Full cool

Heater

side

Restriction on the
aperture enabied
in the VENT mode

Air conditioning
ON mode

Full heat

Set temperature

signal

Mix

actuator

Potentio

meter

Air mix door

In car sensor

Ambient sensor

Sun sensor

Control unit

Air conditioning

switch

Set up temperature

signal

Air conditioning
OFF mode

Total signal

Cooler

side

C01RY00011

AIR CONDITIONING  1B–89

2. Air Flow Control

• In the Auto Mode

The automatic heater/air conditioner control unit
operates on the setup temperature signal and
other sensor signals to derive the total signal.
Then, the control unit adjusts base potential of
the power transistor to match it to the voltage
pattern of the target fan so that stage-less fan
speed control can be achieved.
When solar radiation quantity is detected in the
VENT or B/L mode, the control unit increases the
minimum fan voltage to offset.
When FH or FC is selected from the temperature
control switch, air flow is accordingly fixed to
MAX HI or AUTO HI.

• In the Manual Mode

Air flow specified from the fan switch is entered
to the automatic heater/air conditioner control
unit as the manual signal. The signal modifies
the air flow to the level specified from the fan
switch so that the required fan voltage is
attained.

3. Mode (Blow Port) Control

The automatic heater/air conditioner control unit
operates on the setup temperature from the
control switch, and temperature and solar
radiation quantify from the sensors to determine
the total mode control signal. According to the
pattern specified by this signal, the control unit
selects either one of the VENT, BI-LEVEL, FOOT
or DEF/FOOT mode.
The mode actuator determines the rotation
direction comparing the target position against
the current position being determined by the
position detection signal.
When FH or FC is selected for the temperature
from the temperature control switch, mode is
accordingly fixed to the VENT or FOOT.

• In the manual operation of the mode switch, you

can select a desired blow port mode pressing
the corresponding mode switch.

• Operating the DEF mode switch selects the DEF

for the blow port mode.

4.5

12

(V)

M

MAX
HI Relay

Power

transistor

4.8

10.5

MAX HI

Set up

temperature signal

Control unit

In car sensor

Ambient sensor

Sun sensor

Mode control

signal

Fan switch

AUTO HI

Heater

side

Cooler

side

Total signal

VENT mode

Blower fan motor terminal voltage

C01RY00008

Mode control

DEF / FOOT

Set up temperature

signal

Mode actuator

Mode door

Position

detection

switch

Control unit

In car sensor

Sun sensor

Air conditioning

switch

Mode control

signal

Ambient sensor

FOOT

BI-LEVEL

VENT

Heater

side

Cooler

side

Mode total signal

C01RY00009