A/C COMPRESSOR CONTROL OPERATION [FULL-AUTO AIR CONDITIONER]

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A/C Compressor Automatic Control

•  The climate control unit determines A/C ON/OFF mode based on the air mix actuator opening angle.
•  In A/C ON mode (A/C mode), the A/C signal (magnetic clutch) is turned on/off according to the temperature of the air passing through the evaporator determined by the ambient temperature and the air intake mode.
•  When A/C is in ON mode (ECO mode), an ambient temperature computation value is calculated based on the ambient temperature, set temperature, and temperatures from various sensors. This value is used to determine the temperature of the air passing through the evaporator. The temperature of this air determines whether the climate control unit turns the magnetic clutch (A/C signal) off or on. When the ambient temperatures high/low, the climate control unit lowers/raises the magnetic clutch off temperature.This improves cooling comfort.
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Correction

Defroster correction
•  When the DEFROSTER switch is turned on, the system is switched to A/C ON mode to improve defrosting.During this mode, the A/C signal on/off temperature is determined by the ambient temperature and the air intake mode. However, DEFROSTER correction is not performed with the ambient temperature correction.
Ambient temperature correction
•  When the ambient temperature is -5 °C {23 °F} or less, the A/C signal is fixed at OFF to protect the A/C compressor (to prevent A/C compressor fluid from being pressurized). During this operation, manual operation using the A/C switch is not available.
Window fogging prevention correction at start
•  The A/C compressor does not turn on due to PCM A/C cut-off control just after the engine is started. Therefore, the windshield and front door glass are easily fogged when the heater is turned on and air blows from the defroster. To prevent this, no A/C signal is output from the climate control unit to the PCM for 6 s after the ignition switch is turned to the ON position. The window fogging prevention correction at start is not performed when the airflow mode is in any mode other than HEAT, HEAT/DEF, and DEFROSTER during airflow volume automatic control.

A/C Compressor Manual Control

•  A/C ON or OFF mode is selected by operating the A/C switch.

A/C mode

Operation condition
A/C ON mode
A/C MODE (A/C display)
Fixed in A/C mode.
A/C OFF mode (No display)
Fixed in A/C OFF mode.

A/C signal ON/OFF determination in A/C mode

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