Page 3353 of 4133

Fig. 90: Identifying Auto Button And Temperature Thumbwheel 
AUTO BUTTON, LOCATION / TASK / FUNCTION - GF83.40-P-2147GJ 
MODEL 163 as of 01.09.01 with CODE (580a) Automatic air conditioning in the rear ventilation control 
panel  
Fig. 91: Identifying Auto Button
 
 
Auto 
button, 
locationThe auto button (  ) is located in the center in the upper half of the temperature 
selector wheel (2) on the AAC push-button control module (N22). 
 
Auto 
button, 
purposeBy pressing the auto button (  ) automatic switching is activated. Function feedback 
takes place by means of a red LED. 
 
Auto 
button, 
functionIn addition to regulating the temperature, the blower speed and the air distribution are also 
regulated automatically in automatic mode. The blower speed is continuously controlled 
depending on the temperature difference between the specified and actual values.
 
 Auto button, 
locationThe auto button (  ) is located in the center in the rear ventilation control panel 
(N72/2s3). 
 Auto button, 
purposeBy pressing the auto button (  ) automatic switching is activated. 
Function feedback takes place by means of a red LED. 
 
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1998-2005 HVAC Climate Control - 163 Chassis  
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RESIDUAL HEAT BUTTON, LOCATION / TASK / FUNCTION - GF83.40-P-2148GI 
MODEL 163 as of 01.09.01 with CODE (580a) Automatic air conditioning  
Fig. 92: Identifying Residual Heat Button
 
ELECTRIC FAN ENGINE/AIR CONDITIONING SYSTEM, LOCATION/PURPOSE/FUNCTION - GF83.40-P-2151GH 
MODEL 163 up to 31.8.01 with ENGINE 113.942 /981, 612.963, 628.963  
CONDENSER LOCATION/TASK/FUNCTION - GF83.40-P-2152GC 
 Auto button, 
functionPressing the Auto button 
(  ) enables the air quantity and the air distribution for the rear area to be controlled 
automatically by the AAC push-button control module (N22).
 
 
REST 
button, 
locationThe REST button (  ) is located in the center in the lower half of the 
temperature selector wheel (2) on the AAC push-button control module 
(N22) and is combined with the AC OFF button (  ).
 
 
REST 
button, 
purposeThe REST button (  ) is used to switch the residual engine heat utilization 
system on and off. 
Function feedback takes place by means of a red LED.
 
 
REST 
button, 
function
 GF83.40-P-
2109-01GI
 Electric fan, engine/air 
conditioning GF83.40-P-
2118-02GH
 Electric fan, engine/air 
conditioning, purposeThe electric suction fan engine and AC with integrated 
control (M4/7) serves to cool down the coolant and the 
refrigerant.
 
 Engine/air conditioning 
electric fan, function GF83.40-P-
2118-01GH
 
2001 Mercedes-Benz ML320 
1998-2005 HVAC Climate Control - 163 Chassis  
me  
Saturday, October 02, 2010 3:23:16 PMPage 110 © 2006 Mitchell Repair Information Company, LLC.  
     
        
        Page 3355 of 4133

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, 
locationModel 168GF83.40-P-2120-
02GC
  Model 163GF83.40-P-
2120-02GH
 Condenser taskThe 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 positionThe fluid reservoir is located in the engine compartment on the 
left front next to the condenser 
 Fluid reservoir, 
purposeFiltering 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  
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        Page 3356 of 4133

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, taskThe 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, locationThe air distribution button (  ) is located in the center in 
the rear ventilation control panel (N72/2s3). 
 Air distribution 
button, taskThe 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  
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        Page 3357 of 4133

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, 
purposeThe left auxiliary fan (M4m1) and right auxiliary fan (M4m2) serve 
for cooling the coolant and the refrigerant. 
 Auxiliary fan, 
functionup to 31.08.01GF83.40-P-2115-
01GH
  as of 1.09.01GF83.40-P-2115-
01GI
 
2001 Mercedes-Benz ML320 
1998-2005 HVAC Climate Control - 163 Chassis  
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        Page 3358 of 4133

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, 
locationThe 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, 
taskThe 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  
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        Page 3359 of 4133

ENGINE AND AC ELECTRIC SUCTION FAN WITH INTEGRATED CONTROL, FUNCTION - GF83.40-P-2172-01GI 
Function  
Depending on the refrigerant pressure and/or on the coolant temperature the speed of the engine and AC electric 
suction fan with integrated control (M4/7) is increased infinitely. 
The engine and AC electric suction fan with integrated control (M4/7) receives the coolant temperature from the 
coolant temperature sensor (B11/4) and the refrigerant pressure from the refrigerant pressure and temperature 
sensor (B12/2). 
This input information is compared by the engine and AC electric suction fan with integrated control (M4/7) 
with the stored values and, if necessary, the speed of the engine and AC electric suction fan 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 outside temperature of < or = 15°C. 
The pressure-dependent fan speed remains the same. 
At a driving speed of > 75 km/h. 
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 850 W. 
ELECTRIC SUCTION-TYPE FAN FOR ENGINE AND AC WITH INTEGRATED CONTROL, LOCATION/TASK/FUNCTION 
- GF83.40-P-2172GI 
MODEL 163 as of 1.9.01 with ENGINE 113.965 /981, 612.963, 628.963 with CODE (580a) Automatic air 
conditioning  
MODEL 163 as of 1.9.01 up to 31.8.02 with ENGINE 113.942 with CODE (580a) Automatic air 
conditioning  
 and temperature sensor, 
function GF83.40-P-
2171-01GI
 
2001 Mercedes-Benz ML320 
1998-2005 HVAC Climate Control - 163 Chassis  
me  
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        Page 3360 of 4133
Fig. 96: Identifying Electric Suction-Type Fan For Engine And AC With Integrated Control 
BUTTON FOR REAR AREA AIR DISTRIBUTION, LOCATION/TASK/FUNCTION - GF83.40-P-2173GI 
MODEL 163 as of 01.09.01 with CODE (580a) Automatic air conditioning
 
Electric suction-type fan for 
engine and AC with integrated 
control, location
  
 
Electric suction-type fan for 
engine and AC with integrated 
control, taskThe electric suction-type fan for engine and AC with 
integrated control (M4/7) is used to cool down the 
coolant and the refrigerant.
 
 
Electric suction-type fan for 
engine and AC with integrated 
control, function
 GF83.40-P-
2172-01GI
 
2001 Mercedes-Benz ML320 
1998-2005 HVAC Climate Control - 163 Chassis  
me  
Saturday, October 02, 2010 3:23:16 PMPage 116 © 2006 Mitchell Repair Information Company, LLC.