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A/C COMPRESSOR CONTROL OPERATION

id074000103200

## A/C Compressor Automatic Control

• The climate control unit determines A/C ON/OFF mode based on the ambient temperature. When A/C is in ON 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 temperature is high/low, the climate control unit lowers/raises the magnetic clutch off temperature. This improves cooling comfort.

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1 | A/C mode ON/OFF decision
2 | Ambient temperature
3 | A/C ON
4 | A/C OFF
5 | A/C ON/OFF mode determination when A/C is in ON mode.
6 | Varies with an ambient temperature computation value.
7 | Evaporator temperature
8 | A/C signal on
9 | A/C signal off

### Correction

Defroster correction

  • To improve defrost effect when the DEFROSTER switched on, select A/C mode and set the A/C signal ON/OFF temperature is set at 5.0/4.0 °C {41/39 °F}. However, when in ambient temperature correction, defroster correction does not take place.

Ambient temperature correction

  • When the ambient temperature is below -5 °C {23 °F}, this correction fixes the A/C compressor in OFF mode to protect the A/C compressor (that is, to prevent A/C compressor fluid compression). If the A/C switch is pressed, only the indicator will indicate; the A/C compressor will not operate.

Windshield mist prevention correction

  • To prevent the air blown from the defroster when the heater is started in winter from clouding the windows, the blower motor and the A/C signal output are switched off for 6 s after the ignition is turned to ON position. This control only operates if the airflow is in HEAT, HEAT/DEF, or DEFROSTER mode during airflow volume automatic control.

MAX COLD correction

  • When temperature is set to MAX COLD (temperature setting dial is turned to the left), the A/C signal ON/OFF temperature is at 5.0/4.0 °C {41/39 °F}. However, when in ambient temperature correction, MAX COLD correction does not take place.

## A/C Compressor Manual Control

• A/C ON (A/C mode, ECO mode) 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) | A/C compressor is set in ON mode A/C compressor operates below evaporator freezing level so that the evaporator temperature is within a certain range
ECO MODE (ECO display) | A/C compressor is set in ON mode Magnetic clutch operates at higher evaporator temperature level than manual A/C mode to reduce A/C compressor operation time and improve driving economy
A/C OFF MODE | A/C compressor does not operate

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

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1 | Evaporator temperature
2 | A/C ON
3 | A/C OFF

A/C ON/OFF mode determination in ECO mode

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1 | Varies with an ambient temperature computation value.
2 | Evaporator temperature
3 | A/C ON
4 | A/C OFF