A/C COMPRESSOR CONTROL OPERATION [MZ-CD 1.6 (Y6)]


B3E074061196T03

A/C Compressor Automatic Control

• The climate control unit determines A/C ON/OFF mode based on the ambient temperature.
• The A/C ON mode turns the A/C signal ON/OFF (magnetic clutch ON/OFF) using the refrigerant pressure detected by the A/C compressor cycling switch.

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A/C mode (ON, OFF) determination
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A/C signal (ON, OFF) determination during A/C ON mode
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A/C ON mode
4
A/C OFF mode
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Ambient temperature
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A/C signal ON
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A/C signal OFF
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Operating pressure

Correction

Defroster correction
• When the DEFROSTER switch is turned on, the system is switched to A/C ON 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 system is set to A/C OFF mode 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.
MAX COLD correction
• When the temperature is set to 15.0, the system is switched to A/C ON mode.
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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A/C signal ON
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A/C signal OFF
3
Operating pressure