Control and operating unit comfort automatic air conditioning, task - GF83.40-P-2181-01TT

Fig 1: Identifying Comfort Automatic Air Conditioning Control And Operating Unit Components

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

The comfort AAC [KLA] control and operating unit (N22/7) is used to control the following:

Switching the air conditioning system on and off
Cold/hot interior temperature selection, separate for left and right
Manual blower control
Manual air distribution, separate for left and right
Automatic blower control and air distribution
Air recirculation mode
Defrost function
Rear window heater
Residual engine heat utilization system
Remote control for the rear air conditioning
Activated charcoal filter operation

The comfort AAC control and operating module (N22/7) performs the following actuations:

Via the Control Area Network bus, class B (interior compartment) (CAN B):

Refrigerant compressor and heat exchanger shutoff motor by the driver-side SAM control unit with fuse and relay module
Coolant circulation pump by the passenger-side SAM control unit

Via Controller Area Network bus class C (engine compartment) (CAN-C):

Engine and AC electric suction fan with integrated control via the central gateway control unit, by the CDI control unit (with diesel engines) or the ME-SFI [ME] control unit (with gasoline engines).

Via local interconnect network (LIN):

Blower regulator
Fresh air/air recirculation flaps actuator motor
Left blending air flap actuator motor
Right blending air flap actuator motor
Left defroster vent flap actuator motor
Right defroster vent flap actuator motor
Left footwell flap actuator motor
Right footwell flap actuator motor
Left center air flap actuator motor
Right center air flap actuator motor
Left rear blending air flap actuator motor
Right rear blending air flap actuator motor
Heater booster (for engines 271, 628, 646, 647 and 648)
Control panel rear switch group

The following sensor signals are received by the convenience AAC pushbutton control unit (N22/7):

Directly:
- In-car temperature sensor
- Evaporator temperature sensor
Via CAN-B by the driver-side SAM control unit with fuse and relay module:
- Refrigerant pressure and temperature sensor
- Outside temperature display temperature sensor
- C-AAC [K-KLA] multifunction sensor
- C-AAC [K-KLA] sun sensor (4 in total)
Via CAN-B by the overhead control panel control unit:
- in-car temperature sensor

Display

Display (3)

Various settings made at the comfort AAC [KLA] control and operating unit (N22/7) are indicated in the display (3).

Depending on the setting in the instrument cluster, the temperature is given in the display (3) in either °C or °F.

Operating possibilities

Left air distribution thumb wheel (1)

Right air distribution thumb wheel (5)

The air distribution can be set manually for the left and right side using the left air distribution thumb wheel (1) or the right air distribution thumb wheel (5). The display is provided via an illuminated notch printed in white at the edge of the corresponding thumb wheel.

Left automatic button (13)

Right automatic button (6)

The air volume and the air distribution are regulated automatically after pressing the left automatic button (13) or the right automatic button (6). When the automatic mode is activated, the function LED on the particular active side comes on. The "AUTO" symbol appears in the display (3).

Left temperature rocker (2)

Right temperature rocker (5)

Operating the left temperature rocker (2) or the right temperature rocker (5) sets the desired specified temperature for left or right. The temperature is shown on the display (3).

On/off button (10)

The comfort automatic air conditioning (C-AAC) [K-KLA] can be switched off altogether or switched on again by pressing the ON/OFF button (10). The main air flap is closed or opened accordingly. When switched off, "0" is shown in the display (3).

AC OFF and residual heat button (12)

The refrigerant compressor is switched off by pressing the AC OFF and residual heat button (12). All other functions are retained. Heating or just ventilation can be provided for up to 30 minutes by pressing the AC OFF and residual heat button (12) with circuit 15 OFF or circuit 15C ON. If there is low voltage, the residual heat function is automatically switched off. The flaps are in automatic mode. The blower operates at a set fixed value. "REST" is shown in the display (3).

Rear remote control button (8)

The specified temperature can be set separately for the rear seats by operating the rear remote control button (8). This switches the display (3) to the remote control mode. Approx. 5 s after the last actuation, the display goes out.

Reduce air volume button (11)

Increase air volume button (9)

The air volume can be selected manually by operating the Reduce air volume button (11) or the Increase air volume button (9). The automatic air distribution remains active, provided it is switched on.

Activated charcoal filter button (7)

The activated charcoal filter can be manually switched to the supply air flow by operating the activated charcoal filter button (7). This filters out any unpleasant odors.

Heated rear window switch (N22/7s1)

When the button is pressed, the comfort AAC [KLA] control and operating unit (N22/7) transmits a switch-on request to the rear SAM control unit with fuse and relay module via CAN-B; the function LED in the heated rear window switch (N22/7s1) is switched on at the same time.

Air recirculation switch (N22/7s2)

When the air recirculation switch (N22/7s2) is pressed briefly (< 1.5 s), the main air flap is closed to prevent air entering from outside. The function LED in the air recirculation switch (N22/7s2) lights up during operation. When pressed for a longer period (> 1.5 s), the convenience open/close windows and tilting/sliding roof (SHD) (for code (414) Power glass tilting/sliding roof) function is activated.

Window defrost switch (N22/7s3)

The temperature is set to "maximum" and the air flow distributed to the defroster and lateral nozzles. All the other flaps are closed. The blower voltage is controlled depending on the coolant temperature. The "DEFROST" symbol appears in the display (3) of the comfort AAC [KLA] control and operating unit (N22/7) and in the display of the control panel rear switch group. The function LED in the window defrost switch (N22/7s3) comes on.