Ventilation system, function

P83.10-2606-75

Air outlets

N23 Heater/AC operating unit

General function requirements

 Circuit 15 ON

Ventilation, general

The ventilation system prevents the windows from misting up and ensures that there is a uniform, pleasant temperature in the vehicle interior.

The following components are actuated by the heater/AC operating unit:

 Blower motor (M2) through the fan switch (S98/1) integrated into the heater / A/C control unit

 Blend air flap actuator (M16/8)
(with code (I01) Air conditioning Plus)

 Air recirculation flap actuator motor (M39)
(with code (I01) Air conditioning Plus)

Operating modes

 Fresh air mode

 Air recirculation mode (with code (I01) Air conditioning Plus)

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Fresh air mode

The fresh air is drawn in through the air inlet in the front maintenance flap and routed through the pollen filter into the heater or air conditioner housing. Depending on the preselection via the air distribution rotary switch, the fresh air is passed on via the blend air flap into the vehicle interior through the air ducts and air outlets (arrows).

On vehicles with code (I01) Air conditioning Plus, the blend air flap is actuated via the blend air flap actuator, which is actuated by the heater/AC operating unit depending on the following information:

 Specified temperature set on the temperature preselection slider switch

 Interior temperature

 Temperature on evaporator

 Coolant temperature

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On vehicles without code (I01) Air conditioning Plus, the blend air flap is adjusted mechanically by the temperature preselection slider switch in the heater/AC operating unit by means of a cable.

Depending on how the blend air flap is actuated, it opens and closes the air passage through the heater heat exchanger (except model 451.390/490) or the high voltage PTC heater (N33/5) (in model 451.390/490).

Air recirculation mode (with code (I01) Air conditioning Plus)

By actuating the air recirculation switch (N23s3) on the heater/AC operating unit, the air recirculation flap actuator motor is actuated, which closes the air recirculation flap. As a result, supply of outside air is prevented; the air only circulates in the vehicle interior and unpleasant odors and harmful gases are kept out.

The visual feedback of air recirculation mode takes place via the light-emitting diode integrated in the air recirculation switch.