Mercedes-Benz ML320. Manual — part 687

Fig. 115: Identifying Belt Pulley, Design

BELT PULLEY, LOCATION/TASK/DESIGN/FUNCTION - GF83.55-P-2103P

ENGINE 111, 112, 113, 271, 272, 611, 612, 642, 646 in MODEL 203.0 /2 with CODE (580) Air
conditioning (or Tempmatic for USA) with CODE (580) Automatic air conditioning with CODE (581)
Automatic air conditioning with CODE (581) Comfort automatic air conditioning

ENGINE 111, 112, 271, 272, 611, 612, 646 in MODEL 203.7 with CODE (580) Air conditioning (or
Tempmatic for USA) with CODE (580) Automatic air conditioning with CODE (581) Automatic air
conditioning with CODE (581) Comfort automatic air conditioning

ENGINE 112.942 /970, 113.942 /965 /981, 612.963, 628.963 in MODEL 163 as of 1.9.01 with CODE (580)
Automatic air conditioning

ENGINE 112, 113, 271, 272, 273, 612, 642, 646 in MODEL 209.3

ENGINE 112, 113, 271, 272, 273, 642 in MODEL 209.4

Shown on model 203

2001 Mercedes-Benz ML320

1998-2005 HVAC Climate Control - 163 Chassis

me

Fig. 116: Identifying Belt Pulley And Refrigerant Compressor - Shown On Model 203

PRESSURE RELIEF VALVE, FUNCTION - GF83.55-P-2104-02P

The pressure relief valve is a pressure sensitive wax valve. It is used when all other pressure-dependent safety
devices cannot prevent a pressure rise in the refrigerant compressor (A9).

The wax can withstand a pressure of approx. 35 bar. If the pressure increases to above this value, the wax fuse
is destroyed and pressure is released through the created opening.

PRESSURE RELIEF VALVE, LOCATION / TASK / FUNCTION - GF83.55-P-2104P

ENGINE 111, 112, 113, 271, 272, 611, 612, 642, 646 in MODEL 203.0 /2 with CODE (580) Air
conditioning (or Tempmatic for USA) with CODE (580) Automatic air conditioning with CODE (581)
Automatic air conditioning with CODE (581) Comfort automatic air conditioning

ENGINE 111, 112, 271, 272, 611, 612, 646 in MODEL 203.7 with CODE (580) Air conditioning (or
Tempmatic for USA) with CODE (580) Automatic air conditioning with CODE (581) Automatic air
conditioning with CODE (581) Comfort automatic air conditioning

ENGINE 112.942 /970, 113.942 /965 /981, 612.963, 628.963 in MODEL 163 as of 1.9.01 with CODE (580)
Automatic air conditioning

ENGINE 112, 113, 271, 272, 273, 612, 642, 646 in MODEL 209.3

ENGINE 112, 113, 271, 272, 273, 642 in MODEL 209.4

Belt pulley,
position

The belt pulley (2) is located on the front of the drive shaft on the
refrigerant compressor (A9).

Belt pulley,
task

The belt pulley (2) drives the refrigerant compressor (A9). In addition
the pulley (2) is also used as a torque damper and a torque limiter.

Belt pulley,
design

GF83.55-P-
2103-03P

Belt pulley,
function

GF83.55-P-
2103-02P

2001 Mercedes-Benz ML320

1998-2005 HVAC Climate Control - 163 Chassis

me

Shown on model 203

Fig. 117: Identifying Pressure Relief Valve And Refrigerant Compressor - Shown On Model 203

TEMPERATURE CONTROL, FUNCTION - GF83.57-P-2000GH

MODEL 163 up to 31.08.01 with CODE (580) Air conditioning or Tempmatic for USA

Function

The temperature preselected at the temperature selector wheels is reached or kept constant by:



heating up by the heat exchanger,



heating up by the electric heater booster (with engine 612.963 only)



cooling by the evaporator core,



cooling and reheating (reheat mode).

Heating up

The heating system heat exchanger heats the air passing by, which is then conducted into the vehicle interior by
the air ducts.

Heating up by the electric heater booster

Due to the high level of efficiency of the direct-injection diesel engine, the heat output of the coolant is not
sufficient to heat the fresh air. By installing the electric heater booster, behind the heating system heat
exchanger, this heating capacity deficit is compensated.

Pressure relief
valve, position

The pressure relief valve (3) is located on the refrigerant
compressor (A9).

Pressure relief
valve, task

The pressure relief valve (3) serves to protect the refrigerant
circuit from damage caused by excess pressure.

Pressure relief
valve, function

GF83.55-P-
2104-02P

2001 Mercedes-Benz ML320

1998-2005 HVAC Climate Control - 163 Chassis

me

Cooling down

The thermostatic expansion valve located on the evaporator core serves to expand the liquid refrigerant which is
under high pressure thus lowering its pressure. After this the refrigerant evaporates. The evaporation heat
required for this is taken from the air flowing through the evaporator. The resulting cooled down air then
succeeds in entering the passenger compartment via the air ducts.

Reheat mode

The air which has been cooled down and dehumidified by the evaporator core is heated up again by the heat
exchanger (reheat). This serves to prevent the windows from misting up on the inside.

Temperature selector wheel, location/task/
design/function

GF83.25-P-
2102GC

Heating system heat exchanger, location/
purpose/function

GF83.20-P-
2108GC

Evaporator, location/purpose/design/function

GF83.40-P-
2121GC

Expansion valve, location/task/design/function

GF83.40-P-
2123GC

Refrigerant compressor, location/task/design/ function

GF83.55-P-
2100GH

In-car temperature sensor, location/task/function

with suction jet nozzle up to
30.11.99

GF83.57-P-
2115GH

In-car temperature sensor with ventilation fan,
location/task/function

as of 01.12.99

GF83.57-P-
2107GH

Defroster protection temperature sensor,
location/task/function

GF83.57-P-
2113GH

Blending air flap actuator, location / task / function

GF83.57-P-
2112GC

Outside temperature sensor, location/task/ function

as of 01.12.99

GF83.57-P-
2110GH

Air conditioning control module, location/task/ function

GF83.30-P-
2102GH

All Activity Module, location/task/function

GF54.21-P-
4110GH

Electric heater booster position/task/design/ function

Engine 612.963

GF83.70-P-
4054GH

Temperature regulator microswitch, location/
task/function

Engine 612.963

GF83.70-P-
4055GH

Extended activity module, position/task

GF54.21-P-
4106GH

Extended Activity Module, location/task/design

as of 1.12.99

GF54.21-P-
4107GK

2001 Mercedes-Benz ML320

1998-2005 HVAC Climate Control - 163 Chassis

me