MANUAL AIR CONDITIONER SYSTEM [MANUAL AIR CONDITIONER]
2016 – MX-5 – HVAC
MANUAL AIR CONDITIONER SYSTEM [MANUAL AIR CONDITIONER]
Outline
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The climate control unit performs the following controls based on the input signals from the each dial/switch and each sensor.
|
Control item |
Control description |
|
A/C compressor control |
|
|
Supplementary function |
|
Fail-safe |
Functions
A/C compressor control
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The A/C compressor control turns the A/C on/off based on the climate control unit operation and signals from each sensor.
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A/C compressor manual control
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The climate control unit switches the A/C compressor mode on or off according to the operation of the A/C switch.
|
A/C mode (A/C switch operation) |
A/C indicator light |
|
OFF → ON |
On |
|
ON → OFF |
Off |
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A/C cut-off control
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The PCM performs A/C cut-off control based on the input signal from the climate control unit and outputs an operation signal to the A/C relay (magnetic clutch).(See A/C CUT-OFF CONTROL [SKYACTIV-G 2.0].)
Fail-safe
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If a malfunction is detected by the malfunction detection function, the fail-safe function performs the following controls to prevent malfunction operation of the air conditioner and malfunction of output devices.
Fail-safe function table
|
Part where malfunction is determined |
Malfunction determined when ignition is switched ON |
Ignition switched ON under malfunction condition |
|
Ambient temperature sensor |
Ambient temperature sensor input value is fixed at value right before malfunction |
Ambient temperature sensor input value fixed at 15 °C {59 °F} |
|
Evaporator temperature sensor |
Evaporator temperature sensor input value fixed at 0 °C {32 °F} |
← |
|
Engine coolant temperature sensor |
Engine coolant temperature sensor input value fixed at 85 °C {185 °F} |
← |
|
Air mix actuator (potentiometer) |
Air mix actuator drive signal is stopped right after the malfunction is determined |
Control based on ambient temperature (Reference: Graph 1) |
|
Airflow mode actuator (potentiometer) |
Airflow mode actuator drive signal is stopped right when the malfunction is determined
|
Control based on ambient temperature (Reference: Graph 2)
|
|
Air mix actuator (motor lock) |
Air mix actuator drive signal is stopped right after the malfunction is determined |
Resumes output of the air mix actuator drive signal normally for 20 s after the ignition is switched ON (engine off or on). After that, motor output is stopped if a malfunction is detected. |
|
Airflow mode actuator (motor lock) |
Airflow mode actuator drive signal is stopped right when the malfunction is determined |
Resumes output of the mode actuator drive signal normally for 9 s after the ignition is switched ON (engine off or on). After that, motor output is stopped if a malfunction is detected. |
Block Diagram
System Wiring Diagram
Structural View
Operation
A/C compressor control
1. Based on the operation of each switch/dial and signals (1) from each sensor which change according to the vehicle conditions, the climate control unit performs A/C compressor mode determination (2) when the ignition is switched ON (engine off or on).
2. The climate control unit sends (3) the A/C signal to the PCM according to the result of the A/C compressor mode determination and corrections.
3. The PCM turns the A/C relay on (4) based on the A/C signal and the signals from each sensor which change according to the vehicle conditions.
4. When the A/C relay turns on, the magnetic clutch turns on (5).