Automatic air conditioning pushbutton control module, function

P83.40-2308-04

1 Blower switch

2 Temperature selector wheel

3 Air distribution switch

 Defroster button

 Recirculated air pushbutton

 Auto button

 AC OFF button

 REST button (residual engine heat utilization), is combined with the AC button

 Rear compartment air distribution button

 Rear window heater button

N22 Automatic air conditioning (AAC) pushbutton control module

N22b1 Interior air temperature sensor

Function

The AAC pushbutton control module (N22) makes it possible to make adjustments coming from the driver such as:

 air quantity, by adjusting the blower switch setting (1)

 temperature by setting the temperature selector wheel (2)

 air distribution, by setting the air distribution switch (3)

 defrost function by pressing the defroster button (  )

 recirculated air mode by pressing the recirculated air pushbutton ( )

 automatic air distribution/blower speed by pressing the Auto button (  )

 switching off the cooling by pressing the AC button
(  )

 activating the residual engine heat utilization system with the ignition switched off by pressing the REST button

(  )

 heating the rear window by pressing the rear window heating button (  )

 switching off the air distribution to the rear compartment by pressing the rear compartment air distribution button
(  )

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The control module integrated in the AAC pushbutton control module (N22) looks after all system regulation and control functions such as:

 comparing preselected and actual temperatures and controlling the air temperature at the air outlets

 automatic switchover from fresh air to recirculated air mode

 electrical control of refrigerant compressor

 controlling the auxiliary fan or the electric suction-type fan motor/air conditioning with integrated control

The AAC pushbutton control module (N22) has a diagnostic capability. Consequently, any faults which occur are stored in the fault memory which can be read with the help of the diagnosis assistant system (DAS).

When the AAC pushbutton control module is replaced (N22), variant coding must be carried out using the Diagnosis Assistant System (DAS).

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The AAC pushbutton control module (N22) also performs the following actuations:

 direct: refrigerant compressor; heating water circulation pump;
PTC heater booster (OM 612 only), rear window heater

 via the CAN BUS: auxiliary fan, electric suction-type fan motor/air conditioning with integrated control, blower control and air distribution in the rear compartment (automatic mode)

 via the AC bus: blower motor; 8 stepping motors for air distribution

The following sensor signals are read in by the AAC pushbutton control module (N22):

 direct: temperature sensor evaporator, pressure and temperature sensor refrigerant, in-car temperature sensor, center nozzle vent air temperature sensor, footwell and rear passenger compartment, sun sensor

 via the CAN BUS: Ambient temperature display temperature sensor, sensor for specified values in rear control panel