1997 MERCEDES-BENZ ML320 air condition

Lateral nozzle, location/purpose/function GF83.10-P-
2150GC
Front footwell air outlet, location/purpose/ function GF83.10-P-
2145GC
Rear footwell air outlet, location/purpose/ function GF83.10-P-
2146GC
Heating system heat exchanger, location/
purpose/function GF83.20-P-
2108GC
Fresh air/recirculation flap, location/purpose/ function GF83.20-P-
2111GC
Fresh air/recirculation flap actuator, location/
purpose/function GF83.30-P-
2116GC
Blower switch, location/purpose/design/function GF83.25-P-
2100GC
Air distribution switch, location/purpose/design/
function GF83.25-P-
2101GH
Temperature selector wheel, location/purpose/
design/function GF83.25-P-
2102GC
Air recirculation switch, location/purpose/
design/function GF83.10-P-
2117GH
AC button, location/purpose/function GF83.30-P-
2103GH
AC control module, location/purpose/function GF83.30-P-
2102GH
All-activity module, location/purpose/function GF54.21-P-
4110GH
A/C housing, location/purpose/function GF83.30-P-
2119GH
Auxiliary fan, location/purpose/functionENGINE 111.977, 112.942GF83.40-P-
2162GH
Electric fan motor/air conditioning system,
location/purpose/functionEngine 113.942, 113.981 and
612.963, 628.963GF83.40-P-
2151GH
Condenser, location/purpose/function GF83.40-P-
2152GC
Evaporator location/purpose/design/function GF83.40-P-
2121GC
Fluid reservoir (TAC), location/purpose/function GF83.30-P-
2120GC
Expansion valve, location/purpose/design/ function GF83.40-P-
2123GC
Refrigerant pressure sensor, location/purpose/ function GF83.40-P-
2156GH
Refrigerant compressor, location/purpose/
design/function GF83.55-P-
2100GH

2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
Saturday, October 02, 2010 3:23:15 PMPage 79 © 2006 Mitchell Repair Information Company, LLC.

AUTOMATIC AIR CONDITIONING (AAC), FUNCTION - GF83.40-P-0001GI
MODEL 163 as of 1.9.01 with CODE (580a) Automatic air conditioning
Function
The automatic air conditioning (AAC) is equipped with an electronically regulated cooling, heating and
ventilating system and can be summed up by the following list of subfunctions.
Ventilation
The ventilation ensures that there is a sufficient supply of air within the passenger compartment.
Ventilation is achieved with the support of the blower during normal operation, when vehicle is standing
or to increase the air flow. The air is distributed in the passenger compartment using air distribution flaps.
Automatic air conditioning temperature control
The desired temperature is reached or held constant by cooling or heating the air. Precise temperature
control can be achieved by reading in the various temperature sensors.
Residual engine heat utilization
Electromagnetic clutch, location/purpose/
design/function GF83.55-P-
2101GH
In-car temperature sensor, location/purpose/ functionwith intake jet nozzle up to
30.11.99GF83.57-P-
2115GH
In-car temperature sensor with ventilation blower,
location/purpose/functionas of 1.12.99GF83.57-P-
2107GH
Ice-up protection temperature sensor, location/
purpose/function GF83.57-P-
2113GH
Blending air flap actuator, location/purpose/ function GF83.57-P-
2112GC
Outside temperature sensor, location/purpose/ functionas of 1.12.99GF83.57-P-
2110GH
Electric heater booster, location/purpose/
design/functionEngines 612.963 and 628.963GF83.70-P-
4054GH
Temperature regulator microswitch, location/
purpose/functionEngine 612.963GF83.70-P-
4055GH
Extended activity module, location/purpose GF54.21-P-
4106GH
Extended activity module, location/purpose/ designas of 1.12.99GF54.21-P-
4107GK
CDI control module, location/purpose/functionEngine 612.963GF07.16-P-
3102IA

2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
Saturday, October 02, 2010 3:23:16 PMPage 80 © 2006 Mitchell Repair Information Company, LLC.

The residual engine heat utilization system allows the vehicle to be heated even when the ignition is
switched OFF. To do so the system utilizes the residual heat from the engine and guides it via the
blower into the passenger compartment. The heating water circulation pump ensures that the
coolant is properly circulated.
Automatic air conditioning push-button control module
The automatic air conditioning can be operated by the driver using various tip switches. Apart from this
the push-
button control module reads in different sensor signals, processes them and controls components
in the automatic air conditioning.
Rear ventilation control panel
The operator can intervene in the automatic regulation of the rear ventilation through the automatic air
conditioning by using the rear ventilation control panel and adjust it accordingly to suit needs at any
given time. With the aid of the air distribution switch and blower switch the operator can accommodate
his/her own wishes. The correspondingly altered function is then no longer regulated by the automatic air
conditioning.
By pressing the automatic control button the manually initiated settings can be reset and thus regulated
again by the automatic air conditioning.
Regulation of the air quantity and air distribution ensues thus solely by way of the automatic air
conditioning push-button control module.
Heater circuit
Coolant is heated by the engine. Subsequently, the heated coolant is then routed through the heat exchanger,
where the heat is dissipated to the air in the passenger compartment. The heater return line, in which the heating
water circulation pump is located, takes the coolant back to the coolant pump.
The heating water circulation pump ensures that the coolant is properly circulated.
The coolant flows through the heat exchanger permanently.
Depending upon the desired in-car temperature, regulation is conducted over the blending air flaps, which are
operated by the blending air flap actuator motor.
Heater operation with heater booster in vehicles with OM 612.963
In vehicles equipped with direct-injection diesel engines, an electrical heater booster is additionally installed in
the evaporator housing downstream of the heat exchanger, in order to compensate the heater output deficit
which occurs in the case of certain operating conditions.
The 3 heating elements in the heater booster are supplied with current, as a result of which they are heated and
start to glow. As a result of the structural conditions, it is ensured that the drawn in fresh air flows directly past
the electric heater booster, and is therefore heated.

2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
Saturday, October 02, 2010 3:23:16 PMPage 81 © 2006 Mitchell Repair Information Company, LLC.

Refrigerant circuit
The refrigerant compressor serves to compresses the gaseous refrigerant which heats up during the process, is
then routed into the condenser and thus cooled down. After purification in the fluid reservoir the liquid
refrigerant is injected into the evaporator. The refrigerant is vaporized and cools down. The refrigerant
compressor intakes the refrigerant again which has turned gaseous through the heat absorption process.
TABLE OF CONTENTS, AUTOMATIC AIR CONDITIONING (AAC) FUNCTION DESCRIPTION - GF83.40-P-0999GI
MODEL 163 as of 1.9.01 with CODE (580a) Automatic air conditioning
Ventilation, function GF83.10-P-2000GI
Heater circuit function GF83.20-P-2003GH
Automatic air conditioning push-button control module, function GF83.40-P-2000GI
Rear ventilation control panel, function GF83.40-P-2007GI
Refrigerant circuit function GF83.40-P-2001GI
Temperature control, function GF83.57-P-2000GI
Heater booster (ZUH), function GF83.70-P-0005GH
Residual engine heat utilization system, function GF83.75-P-2000GI
Automatic air conditioning (AAC), function GF83.40-P-
0001GI
Ventilation system function GF83.10-P-
2000GI
Heater circuit function GF83.20-P-
2003GH
Automatic air conditioning push-button control module, function GF83.40-P-
2000GI
Rear ventilation control panel, function GF83.40-P-
2007GI
Refrigerant circuit function GF83.40-P-
2001GI
Temperature control, function GF83.57-P-
2000GI
Heater booster (ZUH), function Engine
612.963GF83.70-P-
0005GH
Start heater operation, function Engine
612.963GF83.70-P-
2000GH
End heater operation, function Engine
612.963GF83.70-P-
2002GH
Regulate heater operation, function Engine
612.963GF83.70-P-
2004GH
Cancel heater operation, function Engine GF83.70-P-

2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
Saturday, October 02, 2010 3:23:16 PMPage 82 © 2006 Mitchell Repair Information Company, LLC.

AUTOMATIC AIR CONDITIONING PUSH-BUTTON CONTROL MODULE, FUNCTION - GF83.40-P-2000GI
MODEL 163 as of 1.9.01 with CODE (580a) Automatic air conditioning
Fig. 69: Identifying Blower Switch , Temperature Selector Wheel, Air Di stribution Switch And Interior
Air Temperature Sensor
Function
The AAC push-button control module (N 22) makes it possible to make adjustments coming from the driver
such as:
air quantity, by adjusting the blower switch setting (1)
temperature by setting the temp erature selector wheel (2)
air distribution, by setting the air distribution switch (3)
defrost function by pressing the defroster button ( )
recirculated air mode by pressing th e recirculated air push-button ( )
automatic air distribution/blower speed by pressing the Auto
switching off the cooling by pressing the AC button ( )
activating the residual engine heat ut ilization system with the ignition switched of f by pressing the REST
button ( )
heating the rear window by pressing the rear window heating button ( )
switching off the air distribution to the rear compartment by pressing the rear compartment air
distribution button ( )
612.9632005GH
Residual engine heat util ization system, function GF83.75-P-
2000GI
Automatic air conditioning sy stem component summary,
location/purpose/design/function GF83.40-P-
9990GI

2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
Saturday, October 02, 2010 3:23:16 PMPage 83 © 2006 Mitchell Repair Information Company, LLC.

The control module integrated in the AAC push-button control module (N22) looks after all system regulation
and control functions such as:
comparing preselected and actual temperatures and controlling the air temperature at the air outlets
automatic switchover from fresh air to recirculated air mode
electrical control of refrigerant compressor
controlling the auxiliary fan or the electric suction-type fan motor/ air conditioning with integrated
control
The AAC push-button control module (N22) has a diagnostic capability. Consequently, any faults which occur
are stored in the fault memory which can be read with the help of the diagnosis assistant system (DAS).
When the AAC push-button control module is replaced (N22), variant coding must be carried out using the
Diagnosis Assistant System (DAS).
The AAC push-button control module (N22) also performs the following actuations:
direct: refrigerant compressor; heating water circulation pump; PTC heater booster (OM 612 only), rear
window heater
via the CAN BUS: auxiliary fan, electric suction-type fan motor/air conditioning with integrated control,
blower control and air distribution in the rear compartment (automatic mode)
via the AC bus: blower motor; 8 stepping motors for air distribution
The following sensor signals are read in by the AAC push-button control module (N22):
direct: temperature sensor evaporator, pressure and temperature sensor refrigerant, in-car temperature
sensor, center nozzle vent air temperature sensor, footwell and rear passenger compartment, sun sensor
via the CAN BUS: Ambient temperature display temperature sensor, sensor for specified values in rear
control panel
REFRIGERANT CIRCUIT FUNCTION - GF83.40-P-2001GH
MODEL 163 up to 31.8.01 with CODE (580) Air conditioning or Tempmatic for USA
Blower switch, location/task/design/function GF83.25-P-2100GI
Temperature selector wheel, location/task/ design/function GF83.25-P-2102GI
Air distribution switch, location/task/design/ function GF83.25-P-2101GI
Defroster button, location/task/function GF83.40-P-2139GI
Recirculating air push-button, location/task/ function GF83.40-P-2145GI
Auto button, location/task/function GF83.40-P-2147GI
AC OFF button, location/task/function GF83.40-P-2107GI
Rest push-button, location/task/function GF83.40-P-2148GI
Rear passenger compartment air distribution button, location/task/function GF83.40-P-2173GI

2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
Saturday, October 02, 2010 3:23:16 PMPage 84 © 2006 Mitchell Repair Information Company, LLC.

Fig. 70: Identifying Refrigerant Circuit Function (Model 163 Up To 31.8.01 With Code (580) Air
Conditioning Or Tempmatic For USA)
The refrigerant compressor (1) driven by motor compresses the gaseous refrigerant, which is thereby heated up
and routed to the condenser (2).
The condenser's (2) surface withdraws the refrigerant's compression heat. When cooling down the refrigerant
liquefies.
When flowing through the fluid reservoir (3) the refrigerant is purified of any chemicals and mechanical
impurities and the water in the refrigerant is separated and collected.
The expansion valve (4) injects the cooled down and liquefied refrigerant in the evaporator (5), which is located
in the fresh air flow. Here the refrigerant is vaporized. This vaporization process then withdraws heat from the
blow-by fresh air which comes in from outside over the pipe and monolith systems with the result that it cools
down.
The humidity carried along with it is converted to condensed water which is routed to the outside. The air is
dried.
The refrigerant compressor (1) draws in the refrigerant which has turned gaseous on account of the heat
absorption and compresses it again.
When the engine is running and the blower switched on, the passenger compartment can have cool air supplied
to it by various outlet nozzles. The intensity of the cooling process depends on the previously set in-car
temperature and the blower output.

2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
Saturday, October 02, 2010 3:23:16 PMPage 85 © 2006 Mitchell Repair Information Company, LLC.

REFRIGERANT CIRCUIT, FUNCTION - GF83.40-P-2001GI
MODEL 163 as of 1.9.01 with code (580a) Automatic air conditioning
Auxiliary fan, location/task/function Engines 111.977, 112.942GF83.40-P-
2162GH
Electric fan motor/air conditioning,
location/task/function Engines 113.942/981 and
612.963GF83.40-P-
2151GH
Condenser position/task/function GF83.40-P-
2152GC
Evaporator, location/purpose/design/function GF83.40-P-
2121GC
Fluid reservoir (TAC), location/task/function GF83.30-P-
2120GC
Expansion valve, location/task/design/function GF83.40-P-
2123GC
Refrigerant pressure sensor, location/task/ function GF83.40-P-
2156GH
Refrigerant compressor, location/task/design/
function GF83.55-P-
2100GH
Air conditioning control module, location/task/
function GF83.30-P-
2102GH
All-activity module, location/task/design/ function GF54.21-P-
4110GH
Extended-activity module, position/task GF54.21-P-
4106GH
Extended-activity module, location/task/designas of 1.12.99GF54.21-P-
4107GK
CDI control module, location/task/function Engine 612.963GF07.16-P-
3102IA

2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
Saturday, October 02, 2010 3:23:16 PMPage 86 © 2006 Mitchell Repair Information Company, LLC.