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Home >> Mercedes Benz >> 2006 >> G55 >> Repair and Diagnosis >> Heating, Ventilation & A/C (HVAC) >> HVAC Control Systems >> HVAC Basic Knowledge -- G-Class (463) - 1 Of 2 >> Basic Knowledge >> Ventilation system, function - GF83.10-P-2000GB

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

MODEL 463.306 /336 /346 as of model year 2011 /YoM 10 

MODEL 463.202 /222 /236 /237 as of model year 2009 /YoM 08 

MODEL 463.247 /248 /249 /254 /270 /271 /303 /340 /341 as of model year 2007 

Illustration of the air outlets in the front 

Fig 1: Ventilation System Function Diagram - Air Outlets In Front
G07740584Courtesy of MERCEDES-BENZ USA

Illustration of the air outlets in the rear 

Fig 2: Ventilation System Function Diagram - Air Outlets In Rear
G07740585Courtesy of MERCEDES-BENZ USA

Illustration of the air outlets in the rear (with code (HH7) Additional air conditioning in rear) 

Fig 3: Ventilation System Function Diagram - With Code (HH7) Additional Air Conditioning In Rear
G07740586Courtesy of MERCEDES-BENZ USA

Function requirements: 

IMPORTANT The EZS control unit (N73) transmits the circuit status via interior CAN.

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.

General function sequence 

Ventilation is provided 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 AAC [KLA] control and operating unit (N22) forwards the request via AC bus to the blower regulator (A32n1), which then actuates the blower motor.

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

The control and operating unit actuates the following components for adjustment of the air ducting flaps via the AC bus:

The ventilation function allows the following operating modes: 

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 housing.

Air recirculation mode function sequence 

Briefly pressing the air recirculation mode button (N22s2) on the control and operating unit closes the fresh air/recirculated air flap and thus prevents the supply of outside air. The air only circulates in the vehicle interior and unpleasant odors and harmful gases are kept out. The function indicator in the air recirculation mode button comes on.

Defrost mode function sequence 

When the defroster button on the control and operating unit is pressed, all air flaps are closed with the exception of the defroster flaps and the air recirculation flap. These are fully opened. The blend air flaps are set to full warm air supply. The blower motor is actuated by the control and operating unit via the blower regulator to ensure the best possible defrost mode dependent on the temperature of the air flowing out.

The refrigerant compressor (A9) is activated in order to ensure that the air flowing out is dried.

Function sequence rear air conditioning ventilation system (with code (HH7) Additional air conditioning in rear) 

Upon actuation of the air volume button (3) integrated in the rear air conditioning control unit (N22/4), the blower motor (M2/1) is actuated via the electronic rear air conditioning blower regulator (N29/2) by means of a direct line corresponding to the selected air volume. The ventilation system ensures that the air is circulated in the rear section of the vehicle interior. The air is sucked in by the rear blower motor and led to the blend air vents via air ducts from where it is distributed in the rear section of the vehicle interior. Using the sliding handles of the blend air vents it is possible to adjust the air flow to the rear passengers' preferences.

IMPORTANT The ventilation function of the rear air conditioning circulates the ambient air. Fresh air supply is not possible.

  Component description of refrigerant compressor A9 GF83.55-P-2108G
  Blower, component description A32m1, A32n1 GF83.10-P-2050G 
  Automatic air conditioning actuator motors, component description M2/5, M2/6, M2/7, M2/15, M2/16 and M2/21 GF83.40-P-2197G 
  Component description for automatic air conditioning control and operating unit N22 GF83.40-P-3000G 
  Electronic ignition/starter switch control unit (EZS), component description N73 GF80.57-P-6000G