MERCEDES-BENZ ML350 1997 Complete Repair Manual

Fig. 71: Identifying Refrigerant Circuit, Function (Model 163 As Of 1.9.01 With Code (580A) Automatic
Air Conditioning)
The refrigerant compressor driven by the motor compresses the gaseous refrigerant, which is thereby heated up
and routed to the condenser.
The refrigerant's compression heat is then withdrawn on the surface of the condenser. While cooling down, the
refrigerant liquefies.
When the refrigerant flows through the fluid reservoir it is cleansed of any chemical and mechanical impurities.
The water contained in the refrigerant is separated and collected.
The expansion valve sprays the cooled and liquefied refrigerant into the evaporator, which is located in the
fresh-air flow. Here the refrigerant is vaporized. Through this evaporation process heat is extracted from the
fresh air flowing past from outside over the tube and fin system so that air cools down.
The air humidity carried along is converted to condensed water, which escapes into the open. The air dries out.
The refrigerant compressor aspirates the refrigerant which has turned gaseous on account of the heat absorption
and then compresses it yet again.
When the engine is running and the blower switched on, the interior can be supplied with cooled air through the
various air outlets. Cooling intensity is dependent upon the preset in-car temperature and blower setting.
Engine 111.977, 112.942, 112.970

2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
Saturday, October 02, 2010 3:23:16 PMPage 87 © 2006 Mitchell Repair Information Company, LLC.

REAR VENTILATION CO NTROL PANEL, FUNCTION - GF83.40-P-2007GI
MODEL 163 as of 1.9.01 with CODE (580a) Automatic air conditioning
N72/2s3 Rear ventilation control panel
Auto button
Air distribution button
Blower button
Auxiliary fan, location/purpose/function
with code 580 up to 31.08.01
Engine 112.942, 112.970 with
code 580a as of 01.09.01GF83.40-P-
2162GH
Engine and AC electric su ction 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 of
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, locati on/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

2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
Saturday, October 02, 2010 3:23:16 PMPage 88 © 2006 Mitchell Repair Information Company, LLC.

Fig. 72: Identifying Rear Ventilation Control Panel
The rear ventilation control panel (N 72/2s3) enables specific settings to be made for the rear compartment
ventilation system.
The following possibiliti es are available:
Setting air quantity by pressi ng the blower button ( )
Air distribution by pressing the air distribution button ( )
Automatic air distribution/blower speed by pressing the Auto button ( ) (Control through AAC push-
button control module (N22))
BLOWER BUTTON, FUNC TION - GF83.40-P-2100-01GI
The blower button ( ) switches a cont rol voltage of 0 - 6 V through to the rear compartment blower control
via the rear ventilation control panel (N72/2s3).
By using several blower steps it is possible to regulate the blower speed between 0-100 %.
The automatic blower function can be set by pressing th e Auto button, whereby control is assumed by the AAC
push-button control module (N22).
AIR DISTRIBUTION BUTTON FUNCTION - GF83.40-P-2101-01GI
Function
By pressing the air distribution button ( ) the rear pa ssenger compartment air distributor flap actuator
motor is regulated by the rear ventil ation control panel. The rear passenger compartment air distributor flap
actuator motor drives the rear passenger compartment ai r distributor flap, which can route the air into two
directions.
Blower button position/task/function GF83.40-P-2144GI
Air distribution button, location/task/function GF83.40-P-2159GI
Auto button, location/task/function GF83.40-P-2147GJ

2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
Saturday, October 02, 2010 3:23:16 PMPage 89 © 2006 Mitchell Repair Information Company, LLC.

Air distribution button ( ) = air duc ting to rear compartment nozzle
Air distribution button ( ) = air ducting to the air outlets in the rear footwell
The automatic air distribution function can be set by pr essing the Auto button, whereby control is assumed by
the AAC push-button c ontrol module (N22).
RECIRCULATING AIR PU SH-BUTTON, FUNCTION - GF83.40-P-2102-01GI
Function
A brief actuation (< 1.5 s) of the recirculating air pus h-button ( ) energizes the actuator motor for the fresh
air/recirculated air flap, whic h activates the fresh air/recirculated air fl ap and thus closes the fresh air duct and
opens the recirculation duct, in or der to enable the air supply from the passenger compartment. The function
LED illuminates during recirculation mode.
Recirculated air convenience closing function
If the recirculating air pus h-button ( ) is pressed for longer than > 2 s, then alongside the recirculation
function, all open windows and the sliding and tilting roof are automatically closed (window and sliding/
tilting roof must ha ve been normalized ). The function LED illuminates durin g recirculation mode. In order to
prevent any current peaks the sliding/tilting sunroof and power windows are actuated successively.
If the push-button is pressed again for > 2 s, the windows a nd the sliding/tilting sunroof return to the previously
stored position and the fresh air/ recirculated air flap moves to the fresh air position (LED off).
The convenience closing function can only be started if the recirculating LED is not illuminated.
Each window, which has been manually opened during the r ecirculation phase, remains in this position if the
recirculating function is cleared: all other windows move to the stor ed positions. The position of the
sliding/tilting sunroof prior to the st art of the closing operation and that of the side windows is stored in the
memory. The windows and the sliding/tilting sunroof wh ich have been closed by the convenience closing
function, remain closed if the recirculation push-
button was only pressed briefly (t < 1.5 s). In this case, only the
fresh air/recirculated air flap is moved to the fresh-air position. The stored positions are cleared when the
ignition is switched off.
AUTOMATIC AIR CONDITIONING BOX FUNCTION - GF83.40-P-2105-02GI
Operating condition: Air ducting under heater operation

2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
Saturday, October 02, 2010 3:23:16 PMPage 90 © 2006 Mitchell Repair Information Company, LLC.

Fig. 73: Identifying Automatic Air Conditioning Box Function - Operating Condition Air Ducting Under
Heater Operation
Operating condition: HEATING Function
When in heating mode, the blower motor (5) draws in fresh air (A) to the automatic air conditioning box and
routes it through the multipurpose filter (3). The air cleaned by the multipurpose filter (3) is then routed to the
evaporator core (2) and dried there. The dried, cooled and filtered air (B) is then routed on through the heat
exchanger (1). This air conduction is controlled via the setting of the blending air flaps (6).
The dried, cooled and filtered air (B) is then heated up again in the hot heat exchanger (1). The warm air (C) is
routed via the air outlets (E, F, FR, M and S) into the vehicle interior.
The fresh air/recirculated air flap (4) is closed.
Operating condition: Air ducting in cooling mode

2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
Saturday, October 02, 2010 3:23:16 PMPage 91 © 2006 Mitchell Repair Information Company, LLC.

Fig. 74: Identifying Automatic Air Conditioning Box Function - Operating Condition Air Ducting In
Cooling Mode
Operating condition: cooling. Function
When in cooling mode, the blower motor (5) draws in fresh air (A) to the automatic air conditioning box and
routes it through the multipurpose filter (3). The air cleaned by the multipurpose filter (3) is then routed to the
evaporator core (2) and dried there. The dried, cooled and filtered air (B) is then routed around the heat
exchanger (1). This air conduction is controlled via the setting of the blending air flaps (6).
The dried, cooled and filtered air (B) is routed directly into the passenger compartment via the air outlets (E, F,
FR, M and S). The fresh air/recirculated air flap (4) is closed.
Operating condition: Air ducting in blending mode (hot/cold) closed-loop operation

2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
Saturday, October 02, 2010 3:23:16 PMPage 92 © 2006 Mitchell Repair Information Company, LLC.

Fig. 75: Identifying Automatic Air Conditioning Box Function - Operating Condition Air Ducting In
Blending Mode (Hot/Cold) Closed-Loop Operation
Operating condition: Blend air (warm/cold) Function
When in blending mode, the blower motor (5) draws in fresh air (A) to the automatic air conditioning box and
routes it through the multipurpose filter (3). The air cleaned by the multipurpose filter (3) is then routed to the
evaporator core (2) and dried there. Some of the dried, cooled and filtered air (B) is routed onwards by the heat
exchanger (1) and some is routed around the heat exchanger (1). This air conduction is controlled via the center
setting of the blending air flaps (6).
The dried, cooled and filtered air (B) which was routed through the heat exchanger (1) is then heated up again.
After passing through the blending air flaps (6) this heated air (C) is mixed up to form blend air (D) with the
dried, cooled and filtered air, which was routed around the heat exchanger (1). This blend air (D) is then routed
via the air outlets (E, F, FR, M and S) into the passenger compartment. The fresh air/recirculated air flap (4) is
closed.
Operating condition: Air ducting "recirculation air" in cooling mode

2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
Saturday, October 02, 2010 3:23:16 PMPage 93 © 2006 Mitchell Repair Information Company, LLC.

Fig. 76: Identifying Automatic Air Conditioning Box Function - Operating Condition Air Ducting
Recirculation Air In Cooling Mode
Operating condition: Cooling down "recirculation air" Function
In cooling mode with recirculated air, the blower motor (5) draws in recirculated air (A) from the passenger
compartment via the opened fresh air/recirculated air flap (4) into the automatic air-conditioning box and routes
it through the multipurpose filter (3). The air cleaned by the multipurpose filter (3) is then routed to the
evaporator core (2) and dried there. The dried, cooled and filtered air (B) is then routed around the heat
exchanger (1). This air conduction is controlled via the setting of the blend air flap (6).
The dried, cooled and filtered air (B) is routed directly into the passenger compartment via the air outlets (E, F,
FR, M and S). The supply of fresh-air is cut off by the fresh air/recirculation flap (4).
AUTOMATIC AIR CONDITIONING BOX, DESIGN - GF83.40-P-2105-04GI
The automatic air conditioning box consists of the following components
Air ducting flaps
Combination filter
Blower motor
Blower regulator
Evaporator
Heating system heat exchanger
Expansion valve

2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
Saturday, October 02, 2010 3:23:16 PMPage 94 © 2006 Mitchell Repair Information Company, LLC.

Blending air flap actuator
Fresh air/recirculated air flap actuator
Defroster vent flap actuator motor
Rear shutoff flap actuator motor
Footwell flap actuator
Electric heater booster (for engine 612.963 only) and therefore forms a complete unit.
AIR CONDITIONER HOUSING, LOCATION / TASK / DESIGN / FUNCTION - GF83.40-P-2105GI
MODEL 163 as of 1.9.01 with code (580a) Automatic air conditioning
Fig. 77: Identifying Automatic Air Conditioning Box


Automatic air
conditioning box,
locationThe Automatic air conditioning box (1) is below the instrument
panel.

Automatic air
conditioning box,
purposeThe automatic air conditioning box distributes the air that is
required to ventilate the vehicle to the relevant air ducts and vents
depending on the interior temperature that is required.


Automatic air
conditioning box,
design
GF83.40-P-
2105-04GI
Automatic air
conditioning box with engine 112, 113GF83.40-P-

2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
Saturday, October 02, 2010 3:23:16 PMPage 95 © 2006 Mitchell Repair Information Company, LLC.

AC OFF BUTTON, FUNCTION - GF83.40-P-2107-01GI
Function
When the AC OFF button ( ) on the automatic air conditioning push-button control module is pressed an
LED comes on, the refrigerant compressor is switched off and cooling therefore switched off The air is no
longer cooled and dried.
Vehicles with diesel engine:
Additionally the electric heater booster is switched off. All other functions are retained.
In order to switch off the refrigerant compressor the push-button control module sends a switch-off request over
the CAN. At the same time, the compressor torque value is set to "0". After a specified time delay the
refrigerant compressor is switched off.
AC OFF BUTTON, LOCATION/TASK/FUNCTION - GF83.40-P-2107GI
MODEL 163 as of 1.9.01 with CODE (580a) Automatic air conditioning
Fig. 78: Identifying Temperature Thumbwheel And AC OFF Button

function2105-02GI
Maximum heating mode for vehicles equipped with engine
612.963 onlyGF83.40-P-
2105-02GJ

AC OFF
button,
locationThe AC OFF button ( ) is located at the center of the lower half of
the temperature selector wheel (2) on the AAC push-button control
module (N22).

AC OFF
button, taskThe AC OFF button ( ) serves to switch the automatic air
conditioning on and off. Function feedback is by way of a red LED.

AC OFF
button,
function
GF83.40-P-
2107-01GI

2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
Saturday, October 02, 2010 3:23:16 PMPage 96 © 2006 Mitchell Repair Information Company, LLC.