MERCEDES-BENZ ML350 1997 Complete Repair Manual

AIR DISTRIBUTION SWITCH, LOCATION/TASK/DESIGN/FUNCTION - GF83.25-P-2101GI
MODEL 163 as of 1.9.01 with code (580a) Automatic air conditioning
Fig. 47: Identifying Air Distribution Switch
- Model 163 As Of 1.9.01 With Code (580a) Automatic Air
Conditioning
TEMPERATURE SELECTOR WHEEL, FUNCTION - GF83.25-P-2102-01GH
Function
Heating
By rotating the temperature selector wheel, a cable is moved via a disk cam, thereby actuating the blending air
flaps.
Air conditioning
The air temperature is regulated by a rotary control with a variable resistor. Signals from the resistor and AAC
control module determine the desired interior temperature. If the temperature selector wheel is turned in an anti-
Air distribution
switch, designThe air distribution switch is designed as a rotary switch with 12
indented positions for air distribution.
Air distribution
switch, function GF83.25-P-
2101-01GH
Air distribution
switch, locationThe air distribution switch (3) is located on the right in the AAC
push-button control module (N22).
Air distribution
switch, taskThe air distribution switch (3) controls the air flow to the air outlets
for ventilation of the passenger compartment.
Air distribution
switch, designThe air distribution switch (3) is equipped with a rotary ring, with
which the air distribution can be set. The LEDs in the rotary ring
display the air distribution level.

Air distribution
switch, function GF83.25-P-
2101-01GI

2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
Saturday, October 02, 2010 3:23:15 PMPage 57 © 2006 Mitchell Repair Information Company, LLC.

clockwise direction to the final indented position (max. cooling), the recirculation switch is bypassed and thus
the fresh air flaps closed, in order to achieve the max. interior cooling (with A/C ON).
TEMPERATURE SELECTOR WHEEL, FUNCTION - GF83.25-P-2102-01GI
Function
The desired in-car temperature is set by turning the temperature selector wheel on the AAC push-button control
module (N22).
The AAC push-button control module (N22) compares the desired temperature with the temperature in the
passenger compartment. The passenger compartment temperature is determined by the in-car temperature
sensor on the AAC push-button control module (N22) and the temperature sensor for the vent air at the center
nozzle, front and rear footwells.
Using the comparison between specified and actual values, the AAC push-button control module (N22)
determines the correct setting of the blending air flaps and actuates these. The selected temperature is reached
and maintained as quickly as possible, if warming or cooling of the interior is necessary.
TEMPERATURE SELECTOR WHEEL, LOCATION - GF83.25-P-2102-02GH
Heater depiction
The temperature selector wheel (2) is located in the heater control unit.
Fig. 48: Identifying Temperature Selector Wheel On Heater Control Unit
- Model 163
TEMPERATURE SELECTOR WHEEL, LOCATION/TASK/DESIGN/FUNCTION - GF83.25-P-2102GC
MODELS 163 up to 31.8.01, 168 up to 28.2.01
Temperature selector
wheel, locationModel 168GF83.25-P-
2102-02GC
Model 163GF83.25-P-
2102-02GH
Temperature selector The temperature selector wheel serves to preselect the

2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
Saturday, October 02, 2010 3:23:15 PMPage 58 © 2006 Mitchell Repair Information Company, LLC.

TEMPERATURE SELECTOR WHEEL, LOCATION/TASK/DESIGN/FUNCTION - GF83.25-P-2102GI
MODEL 163 as of 1.9.01 with code (580a) Automatic air conditioning
Fig. 49: Identifying Temperature Selector Wheel
- Model 163 As Of 1.9.01 With Code (580a) Automatic
Air Conditioning
AIR CONDITIONING (TAC) FUNCTION - GF83.30-P-0001GH
MODEL 163 up to 31.8.01 with CODE (580) Air conditioning or Tempmatic for USA
Function
The air conditioning's electronically controlled cooling, heating and ventilation system keeps the desired in-car
temperature constant. AC button ( ) pressed (illuminates).
wheel, tasktemperature desired in the vehicle interior.
Temperature selector
wheel design
Heater:
Rotary switch with disk cam, pivot, control-sleeve levers, as well
as micro stops and end stops Air conditioning Rotary switch with
potentiometer

Temperature selector
wheel, functionModel 168GF83.25-P-
2102-01GC
Model 163GF83.25-P-
2102-01GH
Temperature selector
wheel, locationThe temperature selector wheel (2) is located in the center in the
AAC push-button control module (N22).
Temperature selector
wheel, taskThe temperature selector wheel (2) serves to preselect the
temperature desired in the vehicle interior.
Temperature selector
wheel designThe temperature selector wheel (2) is equipped with a rotary ring,
with which the temperature values can be set. The LEDs in the
rotary ring display the set temperature level.

Temperature selector
wheel, function GF83.25-P-
2102-01GI

2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
Saturday, October 02, 2010 3:23:15 PMPage 59 © 2006 Mitchell Repair Information Company, LLC.

After starting, the refrigerant compressor starts up. If cooling is not necessary, the refrigerant compressor's
output is lowered and switched off via the icing inhibitor.
The air conditioning is always ready for operation after the engine has been started, and operates according to
the so-called "reheat" principle. This means: The refrigerant compressor always operates at an ambient
temperature in excess of 1°C, therefore also cools cold incoming air. Following the cooling process, the dried
air is heated at the heat exchanger.
On the one hand, this effect serves the purpose of comfort, because cooling also simultaneously causes air
dehumidification which, in turn, is an important prerequisite for a pleasant interior climate. On the other hand,
the air is dried as a result of this cooling and heating, thereby preventing window fogging.
Pressing the AC button again ( ) (does not illuminate) switches off the cooling.
Heating mode
The in-car temperature sensor measures the air temperature in the interior of the vehicle.
The air conditioning control module electronics compares the in-car temperature with the desired temperature
which has been set at the temperature selector wheels.
The microprocessor adjusts the air conditioning electronics or keeps the relevant setting constant as required.
Heater operation with heater booster in vehicles with engine 612.963 as of 12/99
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 any heater output deficit
which exists under certain operating conditions.
The 3 heating elements in the heater booster are supplied with current, whereupon they are heated and they 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.
Cooling mode
The icing inhibitor measures the temperature at the evaporator air outlet, while the interior temperature sensor
determines the relevant in-car temperature.
The air conditioning control module electronics compares the various measured values with the desired
temperature which has been set at the temperature selector wheels.
The microprocessor adjusts the air conditioning or keeps the relevant setting constant as required.
In-car temperature sensor replaced by new typeas of 1.12.99BT83.57-P-0001-04GH
Ventilation, function GF83.10-P-2000GH
Heater circuit function GF83.20-P-2003GH

2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
Saturday, October 02, 2010 3:23:15 PMPage 60 © 2006 Mitchell Repair Information Company, LLC.

AIR CONDITIONING, LOCATION OF COMPONENTS - GF83.30-P-0003-01GH
Location of components in passenger compartment
Fig. 50: Identifying Air Conditioning Components In Passenger Compartment (1 Of 2)

Location of components in passenger compartment
Air conditioning control module function GF83.30-P-2001GH
Refrigerant circuit function GF83.40-P-2001GH
Temperature control, function GF83.57-P-2000GH
Heater booster (ZUH), function Engine 612.963GF83.70-P-0005GH

2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
Saturday, October 02, 2010 3:23:15 PMPage 61 © 2006 Mitchell Repair Information Company, LLC.

Fig. 51: Identifying Air Condi tioning Components In Passenger Compartment (2 Of 2)
Location of components in passenger compartment as of 12/99
Fig. 52: Identifying Air Conditioning Components
- Location Of Components In Passenger

2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
Saturday, October 02, 2010 3:23:15 PMPage 62 © 2006 Mitchell Repair Information Company, LLC.

Compartment As Of 12/99
Location of components in engine compartment
Fig. 53: Identifying Air Conditioning Components
- Location Of Components In Engine Compartment
Location of components, refrigeration technology part up to 11/99

2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
Saturday, October 02, 2010 3:23:15 PMPage 63 © 2006 Mitchell Repair Information Company, LLC.

Fig. 54: Identifying Refr igeration Components - Refrigeration Technology Part Up To 11/99)
Location of components, refrigera tion technology part up to 12/99
Fig. 55: Identifying Refr igeration Components
- Refrigeration Technology Part Up To 12/99

2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
Saturday, October 02, 2010 3:23:15 PMPage 64 © 2006 Mitchell Repair Information Company, LLC.

TABLE OF CONTENTS, AIR CONDITIONING (TAC) FUNCTION DESCRIPTION - GF83.30-P-0999GH
MODEL 163 up to 31.8.01 with code (580) Air conditioning or Tempmatic for USA
AIR CONDITIONING CONTROL MODULE FUNCTION - GF83.30-P-2001GH
MODEL 163 up to 31.8.01 with CODE (580) Air conditioning or Tempmatic for USA
The following components are integrated into the air conditioning control module (S98):
Blower switch (1): with 0 setting and 4 levels.
The blower switch (1) is not available as an individual part.
Temperature selector wheel (2): with the "Blue", non-heating setting and the continuously variable heater
setting.
When set to the indented position "blue" 100 % recirculated air is provided.
Air distribution switch (3): with the settings: Defroster vents, footwell, center plane and intermediate settings.
Recirculation switch ( ) : 100 % recirculation without time limit, when diode illuminates.
AC button ( ): Diode illuminates,
Refrigerant compressor ON cooling mode/air dehumidification Diode is not illuminated, refrigerant compressor
OFF no air dehumidification/coolin
g mode
Air conditioning (TAC) function GF83.30-P-0001GH
Ventilation system function GF83.10-P-2000GH
Heater circuit function GF83.20-P-2003GH
Air conditioning control unit function GF83.30-P-2001GH
Refrigerant circuit function GF83.40-P-2001GH
Temperature control, function GF83.57-P-2000GH
Heater booster, functionEngine 612.963GF83.70-P-0005GH
Starting heater operation, functionEngine 612.963GF83.70-P-2000GH
Terminate heater operation functionEngine 612.963GF83.70-P-2002GH
Regulate heater operation, functionEngine 612.963GF83.70-P-2004GH
Cancel heater operation, functionEngine 612.963GF83.70-P-2005GH
Air conditioning, location of components GF83.30-P-0003-01GH

2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
Saturday, October 02, 2010 3:23:15 PMPage 65 © 2006 Mitchell Repair Information Company, LLC.

Fig. 56: Identifying Blower Switch, Temperature Selector Wheel And Air Distribution Switch
AIR CONDITIONING CONTROL MODULE, LOCATION - GF83.30-P-2102-02GH
The AC control module (N19) is located behind the center console to the left of the evaporator housing.
Fig. 57: Identifying AC Control Module

Blower switch, location/task/design/function GF83.25-P-2100GC
Air distribution switch, location/task/design/ function GF83.25-P-2101GH
Temperature selector wheel, location/task/ design/function GF83.25-P-2102GC
Air recirculation switch, location/task/design/ function GF83.10-P-2117GH
AC button, location/task/function GF83.30-P-2103GH
AC control module location/task/function GF83.30-P-2102GH
All-activity module, location/task/function GF54.21-P-4110GH

2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
Saturday, October 02, 2010 3:23:15 PMPage 66 © 2006 Mitchell Repair Information Company, LLC.