Mercedes-Benz ML320. Manual — part 676

Fig. 73: Identifying Automatic Air Conditioning Box Function - Operating Condition Air Ducting Under
Heater Operation

Operating condition: HEATING Function

When in heating mode, the blower motor (5) draws in fresh air (A) to the automatic air conditioning box and
routes it through the multipurpose filter (3). The air cleaned by the multipurpose filter (3) is then routed to the
evaporator core (2) and dried there. The dried, cooled and filtered air (B) is then routed on through the heat
exchanger (1). This air conduction is controlled via the setting of the blending air flaps (6).

The dried, cooled and filtered air (B) is then heated up again in the hot heat exchanger (1). The warm air (C) is
routed via the air outlets (E, F, FR, M and S) into the vehicle interior.

The fresh air/recirculated air flap (4) is closed.

Operating condition: Air ducting in cooling mode

2001 Mercedes-Benz ML320

1998-2005 HVAC Climate Control - 163 Chassis

me

Fig. 74: Identifying Automatic Air Conditioning Box Function - Operating Condition Air Ducting In
Cooling Mode

Operating condition: cooling. Function

When in cooling mode, the blower motor (5) draws in fresh air (A) to the automatic air conditioning box and
routes it through the multipurpose filter (3). The air cleaned by the multipurpose filter (3) is then routed to the
evaporator core (2) and dried there. The dried, cooled and filtered air (B) is then routed around the heat
exchanger (1). This air conduction is controlled via the setting of the blending air flaps (6).

The dried, cooled and filtered air (B) is routed directly into the passenger compartment via the air outlets (E, F,
FR, M and S). The fresh air/recirculated air flap (4) is closed.

Operating condition: Air ducting in blending mode (hot/cold) closed-loop operation

2001 Mercedes-Benz ML320

1998-2005 HVAC Climate Control - 163 Chassis

me

Fig. 75: Identifying Automatic Air Conditioning Box Function - Operating Condition Air Ducting In
Blending Mode (Hot/Cold) Closed-Loop Operation

Operating condition: Blend air (warm/cold) Function

When in blending mode, the blower motor (5) draws in fresh air (A) to the automatic air conditioning box and
routes it through the multipurpose filter (3). The air cleaned by the multipurpose filter (3) is then routed to the
evaporator core (2) and dried there. Some of the dried, cooled and filtered air (B) is routed onwards by the heat
exchanger (1) and some is routed around the heat exchanger (1). This air conduction is controlled via the center
setting of the blending air flaps (6).

The dried, cooled and filtered air (B) which was routed through the heat exchanger (1) is then heated up again.
After passing through the blending air flaps (6) this heated air (C) is mixed up to form blend air (D) with the
dried, cooled and filtered air, which was routed around the heat exchanger (1). This blend air (D) is then routed
via the air outlets (E, F, FR, M and S) into the passenger compartment. The fresh air/recirculated air flap (4) is
closed.

Operating condition: Air ducting "recirculation air" in cooling mode

2001 Mercedes-Benz ML320

1998-2005 HVAC Climate Control - 163 Chassis

me

Fig. 76: Identifying Automatic Air Conditioning Box Function - Operating Condition Air Ducting
Recirculation Air In Cooling Mode

Operating condition: Cooling down "recirculation air" Function

In cooling mode with recirculated air, the blower motor (5) draws in recirculated air (A) from the passenger
compartment via the opened fresh air/recirculated air flap (4) into the automatic air-conditioning box and routes
it through the multipurpose filter (3). The air cleaned by the multipurpose filter (3) is then routed to the
evaporator core (2) and dried there. The dried, cooled and filtered air (B) is then routed around the heat
exchanger (1). This air conduction is controlled via the setting of the blend air flap (6).

The dried, cooled and filtered air (B) is routed directly into the passenger compartment via the air outlets (E, F,
FR, M and S). The supply of fresh-air is cut off by the fresh air/recirculation flap (4).

AUTOMATIC AIR CONDITIONING BOX, DESIGN - GF83.40-P-2105-04GI

The automatic air conditioning box consists of the following components



Air ducting flaps



Combination filter



Blower motor



Blower regulator



Evaporator



Heating system heat exchanger



Expansion valve

2001 Mercedes-Benz ML320

1998-2005 HVAC Climate Control - 163 Chassis

me