Mercedes-Benz ML320. Manual — part 670

AC CONTROL MODULE LOCATION/TASK/FUNCTION - GF83.30-P-2102GH

MODEL 163 up to 31.8.01 with CODE (580) Air conditioning or Tempmatic for USA

AC BUTTON, FUNCTION - GF83.30-P-2103-01GH

Function

Pressing the AC button (

) switches on the cooling mode.

AC button (

) pressed

Diode is illuminated, cooling mode/air dehumidification, refrigerant compressor ON

AC button (

) not depressed

Diode not illuminated, no air dehumidification/no cooling mode, refrigerant compressor OFF

The AC button (

) is connected to the A/C control module, which regulates the refrigerant compressor

through the all-activity module. The refrigerant compressor is only active when the engine is running and the
blower switched on. To be able to determine the cut-in point for the electromagnetic coupling on the refrigerant
compressor, the all-activity module must receive additional data from the CAN bus, such as, e.g. the engine
speed.

AC BUTTON, LOCATION - GF83.30-P-2103-02GH

The AC button (

) is located in the air conditioning control module (S98).

Air conditioning
control module,
location

GF83.30-P-
2102-02GH

Air conditioning
control module,
task

Control of air conditioning



Recording input signals of various components



Internal processing of input signals



Sending of control signals to various components

Air conditioning
control module,
function

The AC control module records the input signals of various
components, in order to check the preconditions for proper and intended
operation. It sends control signals to the following components:
Blending air flap actuator motor, fresh air/recirculated air flap actuator
motor, All-activity module.
The air conditioning (tempmatic) control module (TAC) receives input
data from the following devices: AC button, in-car temperature sensor,
temperature selector wheel, blower switch, icing protection temperature
switch, blending air flap position signal.

2001 Mercedes-Benz ML320

1998-2005 HVAC Climate Control - 163 Chassis

me

Fig. 58: Identifying AC Button On Air Conditioning Control Module

AC BUTTON, LOCATION/TASK/FUNCTION - GF83.30-P-2103GH

MODEL 163 up to 31.8.01 with CODE (580) Air conditioning or Tempmatic for USA

EVAPORATOR HOUSING, POSITION - GF83.30-P-2104-01GH

The evaporator housing (1) is located below the instrument panel.

Fig. 59: Identifying Evaporator Housing

EVAPORATOR HOUSING, FUNCTION - GF83.30-P-2104-02GH

AC button,
location

GF83.30-P-2103-
02GH

AC button, task

The AC button is used to switch the air conditioning system on
and off.

AC button,
function

GF83.30-P-2103-
01GH

2001 Mercedes-Benz ML320

1998-2005 HVAC Climate Control - 163 Chassis

me

Operating condition: Air ducting in heating mode

Fig. 60: Identifying Evaporator Housing Function - Operating Condition Air Ducting In Heating Mode

Operating condition: HEATING Function

In the heating operating status, the fresh air (A) is drawn in by the blower (5) into the evaporator housing and
routed through the dust filter (3). The air purified by the dust filter (3) is then routed through the evaporator (2)
and dried there. The fresh air (B), which has been dried, cooled and cleaned, is subsequently routed through the
heat exchanger (1). This air conduction is controlled via the setting of the blending air flaps (6).

The fresh air (B), which has been dried, cooled and cleaned, is heated up again in the heat exchanger (1). The
warm air (C) is conducted via the air outlets (E, F, M and S) into the vehicle interior. The 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. 61: Identifying Evaporator Housing Function - Operating Condition Air Ducting In Cooling Mode)

Operating condition: cooling Function

In the cooling operating status, the fresh air (A) is drawn in by the blower (5) into the evaporator housing and
routed through the dust filter (3). The air purified by the dust filter (3) is then routed through the evaporator (2)
and dried there. The fresh air (B), which has been dried, cooled and cleaned, is subsequently routed around the
heat exchanger (1). This air conduction is controlled via the setting of the blending air flaps (6).

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

Operating condition: Blend air ducting (warm/cold) closed-loop operation

2001 Mercedes-Benz ML320

1998-2005 HVAC Climate Control - 163 Chassis

me