S 420 (140.043) V8-4.2L (119.981) (1996)
Control Module HVAC: Description and Operation
Auxiliary Fan Control Module
The auxiliary fan control module switches on the auxiliary fan.
The pushbutton control module controls the AIR control module (N65/1) with a minimum of 3 mA and max. 10 mA.
The AIR control module (N65/1) compares these values with stored values and switches on the auxiliary fan (M4) under the following conditions:
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Outdoor temperature >5 °C
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Refrigerant pressure = 13 bar
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Coolant temperature = 103 °C
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Limp-home mode (e.g. refrigerant pressure > 20 bar)
The auxiliary fan (M4) is switched off under the following conditions:
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Refrigerant pressure = 12 bar
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Coolant temperature = 100 °C