Mercedes-Benz ML320. Service manual — part 678

This input information is relayed by the CDI control module (N3/9) to the integrated control module of the
electric engine/AC intake fan with integrated control (M4/7).

Engines 113.942 and 113.981

The all-activity module (AAM) (N10) receives the coolant temperature via the coolant temperature sensor and
the refrigerant pressure via the refrigerant pressure sensor (B12).

This input information is relayed by the all-activity module (AAM) (N10) to the integrated control module of
the engine and AC electric suction fan with integrated control (M4/7)

There the input information is compared with the stored values and, if necessary, the speed of the engine and
AC electric suction fan with integrated control (M4/7) is increased to 100 %.

The engine and AC electric suction fan with integrated control (M4/7) operates with AC switched on and in the
reheat mode for basic ventilation with a capacity of up to 20 %.

The basic ventilation can be switched off under the following conditions:



At an outdoor temperature of < or = 15°C the value of the outdoor temperature is transmitted from the
outside temperature sensor (B10/5) to the AC control module (N19).

The pressure-dependent fan speed remains the same.



At a vehicle speed of > 75 km/h

The vehicle speed value comes from the traction system control module via the instrument cluster (A1)
and CDI control module (N3/9), to the control module integrated in the electric suction fan engine and
AC with integrated control (M4/7). The pressure-dependent fan speed remains the same.

An overrun time of 60 s can be set in order to ensure that the engine and AC electric suction fan with integrated
control (M4/7) will continue to operate even where the refrigerant compressor is temporarily switched off by
the icing protection.

The engine and AC electric suction fan with integrated control (M4/7) has a power rating of 550W.

ELECTRIC FAN, ENGINE/AIR CONDITIONING, LOCATION - GF83.40-P-2118-02GH

The engine and AC electric suction fan with integrated control (M4/7) is located immediately in front of the
condenser.

2001 Mercedes-Benz ML320

1998-2005 HVAC Climate Control - 163 Chassis

me

Fig. 80: Identifying AC Electric Suction Fan With Integrated Control

CONDENSER FUNCTION - GF83.40-P-2120-01GC

Function

The hot, gaseous refrigerant routed into the condenser passes the heat (compression heat) to the coiled pipes and
slats. These then very quickly absorb the refrigerant's heat and transmit the heat to the outside air passing
through. This in turn cools the refrigerant.

By cooling down, the refrigerant is liquefied (condensed). The liquid heat refrigerant is then carried away from
the condenser and flows into the fluid reservoir.

CONDENSER, LOCATION - GF83.40-P-2120-02GH

The condenser (7) is located directly in front of the radiator.

2001 Mercedes-Benz ML320

1998-2005 HVAC Climate Control - 163 Chassis

me

Fig. 81: Identifying Condenser

EVAPORATOR, FUNCTION - GF83.40-P-2121-01GC

Function

The refrigerant, which is under high pressure, is injected into the evaporator. The evaporator is a disk-type
evaporator made of soldered semicircular disks with louvered corrugated fins by the Valeo company for model
168 and the Denso company for model 163.

The heat that is required for evaporation is extracted from the air flowing past the evaporator, which cools
down. The soldered semicircular disks with louvered corrugated fins or slats provide a large evaporation surface
and guarantee rapid heat exchange.

The moisture that condenses when the air cools is led to the outside via condensation drain hoses.

The condensation also binds the solids in the air and therefore cleans it.

EVAPORATOR, LOCATION - GF83.40-P-2121-02GH

The evaporator (1) is located in the air conditioning box.

2001 Mercedes-Benz ML320

1998-2005 HVAC Climate Control - 163 Chassis

me

Fig. 82: Locating Evaporator

EVAPORATOR, LOCATION/PURPOSE/DESIGN/FUNCTION - GF83.40-P-2121GC

MODELS 163, up to 31.8.01, 168 with code (580) Air conditioning or Tempmatic for USA

MODELS 163 as of 1.9.01 with code (580a) Automatic air conditioning

FLUID RESERVOIR FUNCTION - GF83.40-P-2122-01GI

Function

The liquefied refrigerant enters the fluid reservoir under pressure and flows through a stainless-steel fabric layer
to the filter block. The filter block's pores are matched exactly to the molecular size of the refrigerant. Thus the
refrigerant can flow through the filter block.

All other matter, primarily water, is held back by this molecular filter and deposited. The cleansed refrigerant
then flows through a rising pipe to the expansion valve.

Evaporator,
location

Model 168

GF83.40-P-2121-
02GC

Model 163

GF83.40-P-2121-
02GH

Evaporator,
purpose

The evaporator is used to cool, dehumidify and clean the interior
air.

Evaporator,
design

The evaporator is a disk-type evaporator made of soldered
semicircular disks with louvered corrugated fins.

Evaporator,
function

GF83.40-P-2121-
01GC

2001 Mercedes-Benz ML320

1998-2005 HVAC Climate Control - 163 Chassis

me