1997 MERCEDES-BENZ ML350 sensor

Fig. 85: Identifying Expansion Valve Design
REFRIGERANT PRESSURE SENSOR, FUNCTION - GF83.40-P-2126-01GH
Function
Shutting off the refrigerant compressor
The refrigerant pressure sensor (B12) sends the current value to the All Activity Module (N10). The All
Activity Module (N10) compares this input information with stored values and actuates the refrigerant
compressor.
At the following values, the refrigerant compressor is switched on or off:
refrigerant pressure > 3 bar = refrigerant compressor ON
refrigerant pressure < 2 bar = refrigerant compressor OFF
refrigerant pressure < 26 bar = refrigerant compressor ON
refrigerant pressure > 30 bar = refrigerant compressor OFF
Cut-in of the auxiliary fan (engines 111.977 and 112.942)
The pressure value received from the refrigerant pressure sensor (B12) is recorded by the All Activity Module
(N10) and compared there with a stored value.
As of 12/99, the Extended Activity Module (EAM, N10/1) assumes this task from the All Activity Module
(N10).
At the following values, the auxiliary fan (M4m1, M4m2) is switched on or off:
refrigerant pressure > 16 bar = auxiliary fan ON
refrigerant pressure <12 bar = auxiliary fan OFF
Cut-in of the electric fan for engine/AC (engines 113.942/981 and 612.963)
The pressure value received from the refrigerant pressure sensor (B12) is recorded by the All Activity Module
(N10), sent to the control module inte
grated in the electric fan for engine/AC and compared there with a stored
Expansion valve,
locationModel 168GF83.40-P-2123-
02GC
Model 163GF83.40-P-2123-
02GH
Expansion valve, taskThe expansion valve injects the liquid refrigerant into the
evaporator.
Expansion valve,
function GF83.40-P-2123-
01GC

2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
Saturday, October 02, 2010 3:23:16 PMPage 105 © 2006 Mitchell Repair Information Company, LLC.

value.
At the following values the electric fan for engine/AC (M4/7) is switched on or off:
refrigerant pressure > 20 bar = electric fan for engine/AC ON
refrigerant pressure <12 bar = electric fan for engine/AC OFF
REFRIGERANT PRESSURE SENSOR, LOCATION - GF83.40-P-2126-02GH
The refrigerant pressure sensor (B12) 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).
Fig. 86: Identifying Refrigerant Pressure Sensor

DEFROSTER BUTTON, FUNCTION - GF83.40-P-2139-02GI
Function
Pressing the defroster button ( ) initiates the defrost function.
Function feedback takes place by means of a yellow LED.
The defrost function works according to the following logic:
the heating power is regulated using the outside temperature
the entire air flow is directed at the windshield and the front side windows, and the defroster nozzles are

2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
Saturday, October 02, 2010 3:23:16 PMPage 106 © 2006 Mitchell Repair Information Company, LLC.

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
Saturday, October 02, 2010 3:23:16 PMPage 112 © 2006 Mitchell Repair Information Company, LLC.

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
me
Saturday, October 02, 2010 3:23:16 PMPage 113 © 2006 Mitchell Repair Information Company, LLC.

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
me
Saturday, October 02, 2010 3:23:16 PMPage 114 © 2006 Mitchell Repair Information Company, LLC.

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
Saturday, October 02, 2010 3:23:16 PMPage 115 © 2006 Mitchell Repair Information Company, LLC.

Auto button, location/purpose/functionRear ventilation operating module
2147GI
GF83.40
-P-
2147GJ
AC OFF button, location/purpose/function GF83.40-P-
2107GI
Residual heat button,
location/purpose/function GF83.40-P-
2148GI
Rear compartment air distribution button,
location/purpose/function GF83.40-P-
2173GI
All-activity module,
location/purpose/function GF54.21-P-
4110GH
Air conditioner housing, location/purpose/
design/function GF83.40-P-
2105GI
Auxiliary fan, location/purpose/function
Engine 111.977, 112.942, 112.970
with code 580 up to 31.08.01
Engine 112.942, 112.970 with code
580a as of 01.09.01
GF83.40-P-
2162GH
Engine and AC electric suction fan with
integrated control, location/purpose/function
Engine 113.942 with code 580a up to
31.08.01 Engine 113.981, 113.965,
612.963, 628.963, with code 580a as o
f
01.09.01
GF83.40-P-
2172GI
Condenser, location/purpose/function GF83.40-P-
2152GC
Evaporator location/purpose/design/function GF83.40-P-
2121GC
Fluid reservoir, location/purpose/function GF83.40-P-
2153GI
Expansion valve, location/purpose/design/
function GF83.40-P-
2123GC
Refrigerant pressure and temperature sensor,
location/purpose/function GF83.40-P-
2171GI
Refrigerant compressor, location/purpose/
design/function GF83.55-P-
2100P
Control valve, location/purpose/function GF83.55-P-
2102P
Belt pulley, location/purpose/design/function GF83.55-P-
2103P
Pressure relief valve,
location/purpose/function GF83.55-P-
2104P
In-car temperature sensor location/purpose/
function GF83.57-P-
2115GI
Ice-up protection temperature sensor,
location/ purpose/function GF83.57-P-
2113GH
Blending air flap actuator, location/purpose/ GF83.57-P-

2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
Saturday, October 02, 2010 3:23:16 PMPage 119 © 2006 Mitchell Repair Information Company, LLC.

REFRIGERANT COMPRESSOR, LOCATION - GF83.55-P-2100-01GH
Illustrated up to 31.08.01
The refrigerant compressor (A9) is flanged to the engine at front left
Fig. 98: Identifying Refrigerant Compressor

REFRIGERANT COMPRESSOR, FUNCTION - GF83.55-P-2100-02A
function2112GI
Ambient air temperature sensor, location/
purpose/function GF83.57-P-
2119GI
Outlet air temperature sensor, center nozzle,
location/purpose/function GF83.57-P-
2116GI
Outlet air temperature sensor, front footwell,
location/purpose/function GF83.57-P-
2117GI
Outlet air temperature sensor rear, location/
purpose/function GF83.57-P-
2118GI
Sun sensor, location/purpose/function GF83.57-P-
2111GI
Electric heater booster, location/purpose/
design/functionEngine 612.963GF83.70-P-
4054GH
Extended activity module, location/purpose/
design GF54.21-P-
4107GK
CDI control module,
location/purpose/function GF07.16-P-
3102IA
Table of contents, automatic air conditioning
(AAC) function description GF83.40-P-
0999GI

2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
Saturday, October 02, 2010 3:23:16 PMPage 120 © 2006 Mitchell Repair Information Company, LLC.