MANUAL AIR CONDITIONER CONTROL SYSTEM

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Block Diagram

•  The climate control unit performs the defroster control based on the signal sent from the airflow mode selector dial, and sends an operating signal to the air intake actuator.
•  The climate control unit sends an A/C signal to the PCM via the PJB and instrument cluster based on signals sent from the A/C switch, airflow volume control dial and evaporator temperature sensor.
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1
Airflow mode selector switch (European (L.H.D. U.K.) specs.)
2
Evaporator temperature sensor
3
A/C switch
4
Airflow volume control dial
5
Climate control unit
6
Defroster control (European (L.H.D. U.K.) specs.)
7
A/C compressor control
8
Air intake actuator (European (L.H.D. U.K.) specs.)
9
PJB and instrument cluster
10
Refrigerant pressure switch (HI and LO pressure)
11
Refrigerant pressure switch (medium pressure)
12
A/C cut-off control
13
Idle air control
14
A/C relay
15
Stator and thermal protector
16
Magnetic clutch


Outline of Control System

•  Manual air conditioner defroster control and A/C compressor control.

Control name

Control part
Defroster control (European (L.H.D. U.K.) specs.)
Climate control unit
A/C compressor control
Climate control unit


Defroster Control(European (L.H.D. U.K.) specs.)

1.  When the airflow mode selector dial is turned to DEFROSTER position, a wire moves the airflow mode main link, turning the airflow mode to DEFROSTER.

2.  The defroster switch turns on at the same time, and the CPU sends a signal to turn the air intake mode to FRESH.

3.  The air intake actuator operates and turns the air intake mode to FRESH.

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1
Climate control unit
2
Airflow mode selector dial
3
To DEFROSTER position
4
Defroster switch
5
Wire
6
Airflow mode main link
7
FRESH signal
8
Air intake actuator
9
To FRESH position

X: Operates
–: Does not operate

Airflow mode

Air intake mode (REC switch pushed)

Defroster control
VENT
REC Û FRESH
–
BI-LEVEL
REC Û FRESH
–
HEAT
REC Û FRESH
–
HEAT/DEF
REC Û FRESH
–
DEFROSTER
FRESH
x


A/C Compressor Control

•  The climate control unit sends an A/C signal to the PCM via the PJB and instrument cluster based on signals sent from the A/C switch, airflow volume control dial and evaporator temperature sensor.
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1
Evaporator temperature sensor
2
A/C signal
3
Climate control unit
4
PJB and instrument cluster
5
Output
6
A/C relay
7
Magnetic clutch


A/C signal on/off control

•  The climate control unit turns the A/C signal (magnetic clutch) on and off based on the temperature of the air passing through the evaporator when the A/C switch and airflow volume control dial are on. This keeps the evaporator surface temperature within the specified range, preventing the evaporator from freezing while the airflow volume control dial and A/C switch are turned on.
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1
A/C signal on/off decision
2
Evaporator temperature sensor
3
A/C signal