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Ventilation system, function - GF83.10-P-2000CW

MODEL 204.0 /2 up to Model Year 8 

Air outlets in the passenger compartment (shown on model 204.0 with code (581) Comfort automatic air conditioning) 

Fig 1: Identifying Ventilation System Operation Diagram (Air Outlet In Passenger Compartment)
G07522049Courtesy of MERCEDES-BENZ USA

Function 

The ventilation system prevents windows from fogging up, supplies air to the vehicle occupants, and ensures that uniform and pleasant temperatures in the vehicle interior are reached quickly.

Function requirements  :

IMPORTANT The electronic ignition lock control unit (N73) transmits the terminal status via the interior CAN.

Function sequence, general 

The aeration is controlled with the aid of the blower motor (A32m1). When the fresh air/air recirculation flap is adjusted correspondingly, fresh air is supplied to the air conditioner housing via the air inlet. The automatic air conditioning control and operating unit (N22/7) relays the request to the blower regulator (A32n1), which then actuates the blower motor.

With code (581) Comfort automatic air conditioning, ventilation of the rear compartment is also assisted by the rear blower motor (M2/1). Actuation is taken care of by the control and operating unit via the climate control LIN.

Depending on the current control and operating unit settings, the air is led into the vehicle interior via the air ducts and air outlets.

In order to prevent the windows from fogging up, the defroster flaps and the air recirculation flap are closed and the footwell flaps opened completely t = 2 minutes after circuit 15 has been switched off. After starting the engine, the defroster flaps and footwell flaps remain in this fixed position for 30 s. The air recirculation flap is immediately adjustable. All settings are then enabled again.

The following components are actuated by the control and operating unit via the climate control LIN to adjust the air flaps:

Vehicles with code (581) Comfort automatic air conditioning:

Vehicles without code (581) Comfort automatic air conditioning:

The ventilation function allows the following operating modes: 

Fresh air mode function sequence 

Air recirculation mode function sequence 

The fresh air/recirculated air flap is closed by briefly pressing the air recirculation mode button (N22/7s2) on the control and operating unit, which shuts of the outside air supply. The air only circulates in the vehicle interior and unpleasant odors and harmful gases are kept out. The LED in the air recirculation mode button lights up.

Pressing the air recirculation mode button for t > 1.5 s automatically closes the windows and the tilting/sliding roof (with code (414) Power glass tilting/sliding sunroof) or the panoramic sunroof (with code (413) Panoramic glass sunroof with top sliding sunroof).

The fresh air/recirculated air flap is open and fresh air is delivered into the vehicle interior by the air conditioning housing.

Pressing the air recirculation mode button again returns the windows and the tilting/sliding roof or the panoramic sunroof to their previous positions.

The relevant message is transmitted to the following control units via the interior CAN:

These then close and open the windows, the tilting/sliding roof and the panoramic sunroof.

IMPORTANT The detailed procedure is described in the convenience feature (CF) function.

Pollution-controlled air recirculation mode function sequence 

The pollutant sensor (B31) transmits the outside air pollution values to the control and operating unit via the climate control LIN. The fresh air/recirculated air flap is automatically moved to the recirculated air position as of a certain pollutant concentration. The outside air supply is blocked and only interior air circulation takes place. If the condition for pollution-controlled air recirculation mode exists after the engine has been started, fresh air is supplied for t = 30 s.

Then 80 % pollution-controlled recirculated air is used, and after another t = 10 s 100 % pollution-controlled air is used if necessary. Pollution-controlled air recirculation mode is not indicated by a function LED.

Pollution-controlled air recirculation mode is possible with the following settings:

Defrost mode function sequence 

Pressing the defrost button causes all air flaps apart from the defroster flap and the air recirculation flap to be closed. These are opened all the way. The blend air flaps are all set to full warm air supply. The blower motor is actuated by the control and operating unit via the blower regulator in such a way that optimum defrosting is guaranteed, depending on the outflowing air temperature. The refrigerant compressor is switched on in order to ensure that the outflowing air is dried.

IMPORTANT With code (581) Comfort automatic air conditioning, separate defrosting is provided for the driver via the left defroster vent flap actuator motor and the front passenger via the right defroster vent flap actuator motor.

Without code (581) Comfort automatic air conditioning, defrosting is provided for both the driver and the front passenger via the defroster vent flap actuator motor.

Ram air operation function sequence 

Ram air operation takes place depending on the vehicle speed.

Vehicles without code (581) Comfort automatic air conditioning: Within a vehicle speed range of between v = 60 km/h and v = 160 km/h the fresh air/recirculated air flap is closed by the fresh air/recirculated air flap actuator motor in stages. At speeds of v > 160 km/h the fresh air/recirculated air flap is closed.

Vehicles with code (581) Comfort automatic air conditioning:

Within a vehicle speed range of between v = 60 km/h and v = 160 km/h the ram air flap is closed by the ram air flap actuator motor in stages. At speeds of v > 160 km/h the ram air flap is closed.

REFER TO SYSTEM WIRING DIAGRAMS Electrical function diagram for automatic air conditioning (AAC [KLA]) input signals   PE83.40-P-2052-99FAA
REFER TO SYSTEM WIRING DIAGRAMS Electrical function diagram for automatic air conditioning (AAC [KLA]) actuation   PE83.40-P-2053-99FAA
  Refrigerant compressor, component description A9 GF83.55-P-2109CW
  Blower, component description A32m1 GF83.10-P-2050CW 
  Blower regulator, component description A32n1 GF83.10-P-2051CW 
  Panoramic sliding roof control module, component description A98
With code (413) Panoramic glass sunroof with top sliding sunroof		 GF77.20-P-4106CW
  Pollutant sensor, component description B31
with code (581) Comfort automatic air conditioning		 GF83.10-P-2191CW 
  Rear blower motor, component description M2/1
with code (581) Comfort automatic air conditioning		 GF83.10-P-4160CW 
  Automatic air conditioning actuator motors, component description M2/5, M2/6, M2/7, M2/16 and M16/22
Without code (581) Comfort automatic air conditioning		 GF83.40-P-2197CWA 
M2/5, M2/6, M2/7, M2/8, M2/9, M2/10, M2/11, M2/12, M2/13, M2/21, M2/34 and M2/35 with code (581) Comfort automatic air conditioning GF83.40-P-2197CWB 
  Automatic air conditioning control and operating unit, component description N22/7
Without code (581) Comfort automatic air conditioning		 GF83.40-P-3000CWA
with code (581) Comfort automatic air conditioning GF83.40-P-3000CWB
  Left front door control unit, component description N69/1 GF72.29-P-6001CW
  Right front door control unit, component description N69/2 GF72.29-P-6009CW
  Rear door control unit, component description N69/3, N69/4 GF72.29-P-6021CW
  Overhead control panel control unit, component description N70
With code (414) Power glass tilting/sliding sunroof		 GF82.20-P-5216CW
  Electronic ignition switch control unit, component description N73 GF80.57-P-6001CW
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