1997 MERCEDES-BENZ ML350 AUX

REST BUTTON, FUNCTION - GF83.40-P-2109-01GI
Function
Pressing the reset button ( ) on the AAC push-button control module (N22) switches on the residual engine
heat utilization system. When the engine is switched off, the residual heat heats the vehicle depending on the
temperature setting on the AAC push-button control panel (N22) and the ambient temperature in the vehicle
interior. The vehicle can be heated for approx. 30 min, with the engine switched off. The function is only
available with the ignition switched off or in position 1. If there is low voltage, the residual heat function is
automatically switched off.
The flaps are in automatic mode and the quantity of air is also automatically regulated.
The residual heat function is switched off,
if the electronic key is moved to position 2 in the starter switch,
after approx. 30 minutes,
if the battery voltage drops below 11V.
AUXILIARY FAN, FUNCTION - GF83.40-P-2115-01GH
Function
Depending on the refrigerant pressure and/or the coolant temperature the left auxiliary fan (M4m1), right
auxiliary fan (M4m2) are actuated.
The all-activity module (AAM) (N10) receives the coolant temperature from the coolant temperature sensor and
the refrigerant pressure from the refrigerant pressure sensor (B12).
The all-activity module (AAM) (N10) compares this input information with stored values and actuates the left
auxiliary fan (M4m1), right auxiliary fan (M4m2).
When the following values are indicated the left auxiliary fan (M4m1), right auxiliary fan (M4m2) are switched
on or off:
refrigerant pressure >16 bar = auxiliary fan ON
refrigerant pressure < 12 bar = auxiliary fan OFF
coolant temperature > 105°C = auxiliary fan ON
coolant temperature < 94°C = auxiliary fan OFF
AUXILIARY FAN, FUNCTION - GF83.40-P-2115-01GI
Function
Depending on the refrigerant pressure and/or the coolant temperature the left auxiliary fan (M4m1) and the right
auxiliary fan (M4m2) are actuated.

2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
Saturday, October 02, 2010 3:23:16 PMPage 97 © 2006 Mitchell Repair Information Company, LLC.

The all-activity module (AAM) (N10) receives the coolant temperature by the coolant temperature sensor
(B11/4) and the refrigerant pressure by the refrigerant pressure and temperature sensor (B12/2). The all-activity
module (AAM) (N10) compares this input information with stored values and actuates the left auxiliary fan
(M4m1) and the right auxiliary fan (M4m2).
When the following values are indicated the left auxiliary fan (M4m1), right auxiliary fan (M4m2) are switched
on or off:
refrigerant pressure >16 bar = auxiliary fan ON
refrigerant pressure <13 bar = auxiliary fan OFF
coolant temperature > 105°C = auxiliary fan ON
coolant temperature < 97°C = auxiliary fan OFF
AUXILIARY FAN, LOCATION - GF83.40-P-2115-02GH
The auxiliary fans are located (M4) directly in front of the condenser.
Fig. 79: Identifying Left Auxiliary Fan And Right Additional Fan

ENGINE/AIR CONDITIONING ELECTRIC FAN, FUNCTION - GF83.40-P-2118-01GH
Function
Depending on the refrigerant pressure and/or the coolant temperature the fan speed is increased infinitely.
Engines 612.963 and 628.963
The CDI control module (N3/9) receives the coolant temperature from the coolant temperature sensor and via
the all-activity module (AAM) (N10) via the CAN bus the refrigerant pressure from the refrigerant pressure
sensor (B12).

2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
Saturday, October 02, 2010 3:23:16 PMPage 98 © 2006 Mitchell Repair Information Company, LLC.

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.

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.

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.

Parts ordering notes
INSUFFICIENT AIR CONDITIONING DURING IDLING - AF83.30-P-6007A
MODEL 163.154 #A up to 289564, 163.154 #X, 163.136 /172 with CODE (580) Air conditioning or
Tempmatic for USA
Modification notes
Operation no. of operation texts or standard texts and flat rates
Damage
codeCauseRemedy
83 751
Pressure sensor (B12) occasionally indicates wrong
pressure value to control and operating module
(N19/22) (depending on temperature).
1 Connect pressure gauge and HHT.

Air conditioning/automatic air conditioning
occasionally does not function, refrigerant
compressor does not run.2 Call up air conditioning actual values
with HHT.

3 Compare refrigerant pressure
between pressure gauge (high pressure
side) and HHT.


If pressure difference is greater than
2 bars.?
4 Remove/install/replace pressure
sensor on receiver/drier.

Part no.DesignationQuantity
140 830 00 72Pressure sensorAs required
21.6.04Work steps 1-2 erased
CategoryOp.
no.Operation textTimeAcc.
no.Code
P023731Install modified wiring harness for auxiliary fan (after
checking)015
WU--
Damage
codeCauseRemedy
50 041 73
Fuse f44 blows due to
repeated switch-on of
additional fan
1 Check whether service auxiliary wiring harness (2)
for additional fan has already been installed
The original additional fan connector (M4x1) is
already fastened next to the new additional fan
connector (3) with adhesive tape.


If auxiliary wiring harness (2) is already
installed: ?
2 Ensure that a 40 A fuse is located at position f44


2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
Saturday, October 02, 2010 3:23:17 PMPage 156 © 2006 Mitchell Repair Information Company, LLC.

Fig. 130: Identifying Fuse And Relay Module, Additional Fan Connector And Plug Connector, Blue
NO REFRIGERATION/HEAT FROM AUTOMATIC AIR CONDITIONER - AF83.40-P-3400A
MODEL 163.### #A as of 289565 up to 458809, 163.### #X as of 754620 up to 777100
Operation no. of operation texts or standard texts and flat rates
If an auxiliary wiring harness (2) has not yet been
installed: ?
3 Install auxiliary wiring harness.SM83.30-P-
0009GH

If an additional wiring harness and a 40 A fuse are
already installed and the auxiliary fan does not
function: ?
4 Perform corresponding diagnosis and repair.

CategoryOp. no.Operation textTimeAcc. no.Code
P831917Replace air conditioning operating unit014 WU--
Damage
codeCauseRemedy
83 491 90The air mixing flap is not actuated by the AAC [KLA]
control and operating unit (N22) because the voltage in
the vehicle electrical system is too low during cold start.
1 Replace AAC [KLA]
control and operating
AR83.40-P-

2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
Saturday, October 02, 2010 3:23:17 PMPage 157 © 2006 Mitchell Repair Information Company, LLC.