Automatic air conditioning control and operating unit, component description

P83.40-4029-74

N22 AAC [KLA] control and operating unit

Location

The control and operating unit is located in the center console.

Design

The control and operating unit contains the following controls and displays:

- Left temperature selector wheel (1)

- Blower selector wheel (2)

- Air distribution selector wheel (3)

- Right temperature selector wheel (4)

- A/C, REST button (5)

- Defrosting button (6)

- AUTO button (7)

- In-car temperature sensor (N22b1)

- Heated rear window switch (N22s1)

- Air recirculation switch (N22s2)

The control and operating unit has the following tasks:

 Operation of the vehicle's climate control

 Reading in of sensors

 Evaluation of input factors

 Actuation of components

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Operation of the vehicle's climate control

The control and operating unit enables the following operations:

- Interior temperature separately for the left and right sides

- Manual blower control and air distribution

- Automatic blower control and air distribution

- Automatic air conditioning

- Refrigerant compressor (A9)

- Defrost function

- Residual engine heat utilization

- Recirculated air mode

- Heated rear window (R1)

Interior temperature

The desired temperature setting for the left and right sides can be set by turning the associated temperature selector wheel. The selected specified temperature is displayed via LEDs at the border of the temperature selector wheel.

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Manual blower control

Turning the blower selector wheel enables the air volume to be manually set. The selected blower setting is displayed via LEDs at the border of the blower selector wheel.

Manual air distribution

The air distribution selector wheel can be used to manually set the air distribution. The selected air distribution is displayed via LEDs at the border of the air distribution selector wheel.

Automatic blower control and air distribution

The air volume and the air distribution are regulated automatically when the AUTO button is pressed. If the automatic operation is activated, the LED in the AUTO button lights up.

Refrigerant compressor

Pressing the A/C REST button switches off the refrigerant compressor.

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All other functions of the automatic air conditioning are retained.

The light emitting diode in the A/C, REST button illuminates when the refrigerant compressor is switched on.

Defrost function

Pressing the defroster button sets the temperature to "maximum" and the air flow is distributed to the defroster and side air vents. All the other flaps are closed. The blower output is regulated to match the coolant temperature.

If the function is activated, the light emitting diode in the defroster button lights up.

Residual engine heat utilization

With circuit 15C or circuit 15R ON, the residual engine heat utilization function is activated by pressing the A/C, REST button. The light emitting diode in the A/C, REST button illuminates when the residual engine heat utilization function is active.

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Recirculated air mode

When the air recirculation switch on the control and operating unit is pressed for t < 1.5 s, the fresh air/air recirculation flap is closed, and thus the supply of outside air is prevented. The air only circulates in the vehicle interior and unpleasant odors and harmful gases are kept out. The LED in the air recirculation switch comes on. When the air recirculation switch is pressed for t >
1.5 s, the windows and the panoramic roof (with code (413) Panoramic glass sunroof with top sliding sunroof) are automatically closed. Pressing the air recirculation switch again for t > 1.5 s causes the windows and the panoramic roof to return to their previous positions.

Rear window defroster

The rear window heater is switched on when the rear window heater switch is pressed. The LED illuminates during operation.

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Reading in of sensors

The input factors are read in with the following connections:

 Direct line

 Interior CAN

Direct line

The signals of the evaporator temperature sensor (B10/6) are read in via a direct line.

Interior CAN

The following signals are read in via the interior CAN:

- Refrigerant pressure, provided by the front SAM control unit with fuse and relay module (N10/1)

- Outside temperature, provided by the front SAM control unit

- Interior temperature in the vicinity of the roof, provided by the overhead control panel control unit (N70)

- Coolant temperature, provided by the EIS [EZS] control unit (N73)

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- The vehicle speed, provided by the instrument cluster (A1)

- The door status, provided by the rear SAM control unit with fuse and relay module (N10/1)

Evaluation of input factors

The input factors that have been read in are evaluated by the integrated microprocessor and the relevant components are then actuated.

Actuation of components

Components are actuated with the following lines:

 AC bus

 Interior CAN

 Engine compartment CAN

AC bus

The following components are actuated via the AC bus:

- Blower regulator (A32n1)

- Fresh air/air recirculation flaps actuator motor (M2/5)

- Left blend air flap actuator motor (M2/6)

- Right blend air flap actuator motor (M2/7)

- Footwell flap actuator motors left and right (M2/15)

- Defroster vent flap actuator motors left and right (M2/16)

- Fresh air flaps actuator motor (M2/21)

Interior CAN

The following components are actuated via the interior CAN:

- Refrigerant compressor control valve via the front SAM control unit

- Heater circulation pump (M13) via the front SAM control unit

- The heated rear window via the rear SAM control unit

Engine compartment CAN

The following component is actuated via the engine compartment CAN:

- Engine and air conditioning electric suction fan with integrated control (M4/7) by the CDI control unit (N3/9) (with diesel engine) or the ME-SFI [ME] control unit (N3/10) (with gasoline engine)