Mercedes-Benz ML320. Manual — part 681

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

MODEL 163 as of 1.9.01 with CODE (580a) Automatic air conditioning

FLUID RESERVOIR, LOCATION/PURPOSE/FUNCTION - GF83.40-P-2153GI

MODEL 163 (except 163.128) as of 1.9.01 with CODE (580a) Automatic air conditioning

Fig. 93: Identifying Fluid Reservoir

Condenser,
location

Model 168

GF83.40-P-2120-
02GC

Model 163

GF83.40-P-
2120-02GH

Condenser task

The condenser ensures that the state of the refrigerant coming from
the compressor changes from gaseous to liquid.

Condenser
function

GF83.40-P-
2120-01GC

Receiver position

The fluid reservoir is located in the engine compartment on the
left front next to the condenser

Fluid reservoir,
purpose



Filtering chemical and mechanical impurities out of the
refrigerant



Volume reservoir for the refrigerant

2001 Mercedes-Benz ML320

1998-2005 HVAC Climate Control - 163 Chassis

me

REFRIGERANT PRESSURE SENSOR, LOCATION/TASK/FUNCTION - GF83.40-P-2156GH

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

AIR DISTRIBUTION BUTTON, LOCATION/TASK/FUNCTION - GF83.40-P-2159GI

MODEL 163 as of 01.09 01 with CODE (580a) Automatic air conditioning in the rear ventilation control
panel

Fig. 94: Identifying Air Distribution Button

AUXILIARY FAN, LOCATION/PURPOSE/FUNCTION - GF83.40-P-2162GH

MODEL 163 up to 31.8.01 with ENGINE 111.977,112.942 /970 with CODE (580) Air conditioning or
Tempmatic for USA



Draining the refrigerant

Receiver, function

GF83.40-P-2122-
01GI

Refrigerant pressure
sensor, location

GF83.40-P-
2126-02GH

Refrigerant pressure
sensor, task

The refrigerant pressure sensor (B12) detects the refrigerant
pressure and sends it to the All Activity Module.

Refrigerant pressure
sensor, function

GF83.40-P-
2126-01GH

Air distribution
button, location

The air distribution button (

) is located in the center in

the rear ventilation control panel (N72/2s3).

Air distribution
button, task

The air distribution button (

) controls the air

distribution to the rear area nozzle and the rear legroom air outlets
for ventilating the rear area.

Air distribution push-
button function

GF83.40-P-
2101-01GI

2001 Mercedes-Benz ML320

1998-2005 HVAC Climate Control - 163 Chassis

me

MODEL 163 as of 1.9.01 with ENGINE 112.942 /970 with CODE (580a) Automatic air conditioning

REFRIGERANT PRESSURE AND TEMPERATURE SENSOR, FUNCTION - GF83.40-P-2171-01GI

Detecting the refrigerant pressure

The refrigerant pressure and temperature sensor (B12/2) detects the refrigerant pressure and sends the
determined value via the CAN-BUS to the AAC push-button control module (N22). This value is compared
with a stored temperature/pressure curve.

The refrigerant pressure and temperature sensor (B12/2) operates in a pressure value range of from 0 to 35 bar.

Shutting of the refrigerant compressor

At the following values, the refrigerant compressor is switched off.



refrigerant pressure < 1.75 bar = refrigerant compressor OFF



refrigerant pressure > 30 bar = refrigerant compressor OFF

Switching on the refrigerant compressor

The refrigerant compressor is switched on at the following value



refrigerant pressure > 2.25 bar = refrigerant compressor ON

Detecting the refrigerant temperature

The refrigerant pressure and temperature sensor (B12/2) detects the temperature of the refrigerant and sends the
determined value via the CAN-BUS to the AAC push-button control module (N22). This value is compared
with a stored temperature/pressure curve and the refrigerant level is determined as a result.

With a refrigerant level that is too low, the refrigerant compressor is switched off by the AAC push-button
control module (N22) via the CAN-BUS.

The AC OFF mode is activated and can no longer be quit. Only when the error has been eliminated and the
diagnostic trouble code memory in the AAC push-button control module (N22) has been erased will the system
be operational again.

Auxiliary fan,
location

GF83.40-P-2115-
02GH

Auxiliary fan,
purpose

The left auxiliary fan (M4m1) and right auxiliary fan (M4m2) serve
for cooling the coolant and the refrigerant.

Auxiliary fan,
function

up to 31.08.01

GF83.40-P-2115-
01GH

as of 1.09.01

GF83.40-P-2115-
01GI

2001 Mercedes-Benz ML320

1998-2005 HVAC Climate Control - 163 Chassis

me

The refrigerant pressure and temperature sensor (B12/2) operates in a temperature value range of from -10°C to
+90°C.

Cut-in of electric suction-type fan for engine and AC with integrated control (M4/7)

At the following values the electric suction-type fan for engine and AC with integrated control (M4/7) is
actuated:



refrigerant pressure < 14 bar = fan OFF



Refrigerant pressure > 20 bar = fan ON (100 %)



refrigerant pressure 14 to 20 bar = Continuous linear increase in fan speed (20 -100 %)

REFRIGERANT PRESSURE AND TEMPERATURE SENSOR POSITION/TASK/FUNCTION - GF83.40-P-2171GI

MODEL 163 as of 01.09.01 with CODE (580a) Automatic air conditioning

Fig. 95: Identifying Refrigerant Pressure And Temperature Sensor

Refrigerant pressure
and temperature sensor,
location

The refrigerant pressure sensor (B12/2) is located at the front left
in the engine compartment at the high-pressure line (8) between
the refrigerant compressor (A9) and the capacitor (7).

Refrigerant pressure
and temperature sensor,
task

The refrigerant pressure and temperature sensor (B12/1) detects
the refrigerant pressure and the refrigerant temperature and sends
these values to the AAC push-button control module (N22).

Refrigerant pressure

2001 Mercedes-Benz ML320

1998-2005 HVAC Climate Control - 163 Chassis

me