GF83.10-P-2000FQ Ventilation System, Function
GF83.10-P-2000FQ Ventilation System, Function
MODEL 218
Air outlets in the vehicle (shown on model 218.3)
Function requirements, general
^ Circuit 15 ON
Status of circuit 15 is sent by electronic ignition lock control unit (N73) via interior CAN (CAN B).
Ventilation, general
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.
When the fresh air/recirculated air flap is adjusted correspondingly, fresh air is supplied to the air conditioner housing via the air inlet.
Depending on the current settings on the AAC [KLA] control and operating unit (N22/7), the air is routed into the vehicle interior through air ducts and air outlets.
To prevent the windows from fogging up the defroster flaps are closed t = 2 min. after switching off circuit 15.
After starting the engine, the defroster flaps remain in this fixed position for approx. t = 30 s. After that, all adjustments are possible again.
If a door is opened with circuit 15 OFF, the fresh air/recirculated air flap is opened 50 % by the fresh air/recirculated air flap actuator motor (M2/5) and the ram air flap by the ram air flap actuator motor (M2/34) (with code (581) Comfort automatic air conditioning).
This achieves a significant reduction in the door closing forces.
The function can be set with the diagnostic tester.
The ventilation function encompasses the following subfunctions:
^ Function sequence for AC component actuation
^ Fresh air mode function sequence
^ Air recirculation mode function sequence
^ Function sequence for ram air operation
Function sequence for AC component actuation
The function sequence for actuating the A/C components encompasses the following subfunctions:
^ Function sequence, actuation of blower motor (A32m1)
^ Function sequence for actuation of the air ducting flaps
Function sequence, actuation of blower motor
Ventilation is achieved with the aid of the blower motor. The AAC [KLA] control and operating unit forwards the request straight to the blower regulator (A32n1), which then actuates the blower motor.
With code (581) Comfort automatic air conditioning, the ventilation of the rear passenger compartment is also supported by the rear blower motor (M2/1). The rear blower motor is actuated via climate control LIN (LIN B8) by the control and operating unit
With active voice control system, the blower output is limited. For this purpose, the radio with auto pilot system (A2/56) (with code (511) Audio 50 APS with DVD changer) or COMAND control unit (A40/3) (with code (512) COMAND APS with DVD changer or with code (527) COMAND APS with single DVD drive (with navigation)) sends the status of the voice control system to the control and operating unit via interior CAN. This then limits the blower output.
Air ducting flaps actuation function sequence
The air distribution in the vehicle interior is controlled by corresponding adjustment of the air duct flaps in the air conditioning housing.
The control and operating unit actuates the following components over the climate control LIN:
Vehicles without code (581) Comfort automatic air conditioning:
- For fresh air/recirculated air control and for ram air control:
- Fresh air/recirculated air flap actuator motor
- for temperature control:
- Left blend air flap actuator motor (M2/6)
- Right blend air flap actuator motor (M2/7)
- for ventilation control:
- Defroster flap actuator motor (M2/16)
- Air distribution flap actuator motor (M16/22)
Vehicles with code (581) Comfort automatic air conditioning:
- for fresh air/recirculated air control:
- Fresh air/recirculated air flap actuator motor
- for temperature control:
- Left blend air flap actuator motor
- Right blend air flap actuator motor
- Rear blend air flap actuator motor (M2/35)
- for ventilation control:
- Left defroster flap actuator motor (M2/8)
- Right defroster flap actuator motor (M2/9)
- Left footwell flap actuator motor (M2/10)
- Right footwell flap actuator motor (M2/11)
- Left center air vent flap actuator motor (M2/12)
- Right center air vent flap actuator motor (M2/13)
- Diffuser flap actuator motor (M2/21)
- For ram air control:
- Ram air flap actuator motor
Fresh air mode function sequence
The fresh air/recirculated air flap is open and fresh air is delivered into the vehicle interior through the air conditioner - Fresh air/recirculated air flap actuator motor housing.
Air recirculation mode function sequence
The air recirculation mode function sequence includes the following subfunctions:
^ Function sequence for air recirculation mode using air recirculation mode button (N22/7s2)
^ Pollutant-controlled air recirculation mode function sequence (with code (581) Comfort automatic air conditioning)
Function sequence for air recirculation mode using air recirculation mode button
When the air recirculation mode button on the control and operating unit is closed for t < 1.5 s, the fresh air/recirculated air flap is closed to prevent air flow from outside. The air only circulates in the vehicle interior and unpleasant odors and harmful gases are kept out.
The LED above the air recirculation mode button is illuminated during the air recirculation mode.
Pressing the air recirculation mode button for t > 1.5 s activates comfort air recirculation closing.
The side windows and the tilting/sliding roof (SHD) (with code (414) Power glass tilting/sliding sunroof) are closed in the process.
If the air recirculation mode button is pressed again for t > 1.5 s, the side windows and the tilting/sliding roof return to their previous positions.
Side windows or the tilting/sliding roof that were manually opened during the air recirculation phase do not return to their previous positions once the phase is over.
On vehicles with code (460) Canada version and code (494) USA version, comfort recirculation closing is not possible.
The detailed comfort air recirculation closing procedure is described in the separate convenience feature (CF [KFB]) function description.
Additional function requirements for pollutant-controlled air recirculation mode (with code (581) Comfort automatic air conditioning)
^ Refrigerant compressor (A9) switched on
^ Defrost mode not active
Pollutant-controlled air recirculation mode function sequence (with code (581) Comfort automatic air conditioning)
The pollutant sensor (B31) sends the pollutant values for the outside air over the climate control LIN to the control and operating unit. As of a certain pollutant concentration, the fresh air/recirculated air flap is automatically set to the recirculated air position. Outside air supply is prevented and only the inside air is recirculated. If the conditions for pollutant-controlled air recirculation mode exist after the engine is started, a supply of fresh air is first provided for t = 30 s.
After that, operation continues with 80 % pollutant-controlled recirculated air and after another t = 10 s, as required, with 100 % pollutant-controlled recirculated air.
The pollutant-controlled air recirculation mode is not shown by the illumination of the light-emitting diode in the air recirculation mode button.
Function sequence for ram air operation
The speed-dependent ram air flap is adjusted to prevent the air feed in the interior compartment from increasing when the speed increases. The higher the speed, the further the ram air flap is closed..
The speed signal is sent by the instrument cluster (A1) to the control and operating unit over the interior CAN. It actuates the fresh air/ recirculated air flap actuator motor (without code (581) comfort automatic air conditioning) or ram air flap actuator motor (with code (581) comfort automatic air conditioning ) speed-dependent.
