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Fig. 81: Identifying Condenser
EVAPORATOR, FUNCTION - GF83.40-P-2121-01GC
Function
The refrigerant, which is under high pressure, is injected into the evaporator. The evaporator is a disk-type
evaporator made of soldered semicircular disks with louvered corrugated fins by the Valeo company for model
168 and the Denso company for model 163.
The heat that is required for evaporation is extracted from the air flowing past the evaporator, which cools
down. The soldered semicircular disks with louvered corrugated fins or slats provide a large evaporation surface
and guarantee rapid heat exchange.
The moisture that condenses when the air cools is led to the outside via condensation drain hoses.
The condensation also binds the solids in the air and therefore cleans it.
EVAPORATOR, LOCATION - GF83.40-P-2121-02GH
The evaporator (1) is located in the air conditioning box.
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1998-2005 HVAC Climate Control - 163 Chassis
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Fig. 82: Locating Evaporator
EVAPORATOR, LOCATION/PURPOSE/DESIGN/FUNCTION - GF83.40-P-2121GC
MODELS 163, up to 31.8.01, 168 with code (580) Air conditioning or Tempmatic for USA
MODELS 163 as of 1.9.01 with code (580a) Automatic air conditioning
FLUID RESERVOIR FUNCTION - GF83.40-P-2122-01GI
Function
The liquefied refrigerant enters the fluid reservoir under pressure and flows through a stainless-steel fabric layer
to the filter block. The filter block's pores are matched exactly to the molecular size of the refrigerant. Thus the
refrigerant can flow through the filter block.
All other matter, primarily water, is held back by this molecular filter and deposited. The cleansed refrigerant
then flows through a rising pipe to the expansion valve.
Evaporator,
locationModel 168GF83.40-P-2121-
02GC
Model 163GF83.40-P-2121-
02GH
Evaporator,
purposeThe evaporator is used to cool, dehumidify and clean the interior
air.
Evaporator,
designThe evaporator is a disk-type evaporator made of soldered
semicircular disks with louvered corrugated fins.
Evaporator,
function GF83.40-P-2121-
01GC
2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
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Whenever the system is opened, the fluid reservoir should be replaced because of the water which has
collected there in the meantime.
EXPANSION VALVE, FUNCTION - GF83.40-P-2123-01GC
Function
When the refrigerant compressor is switched on the pressure in the evaporator drops, thereby causing the
diaphragm (1) to curve downwards. The control valve (3) follows the movement of the diaphragm and presses
the ball (4) out of its seating against the spring (5). The opened valve enables the refrigerant to be sprayed into
the evaporator.
As the diaphragm movement (1) is dependent on both the intake pressure and the temperature at the evaporator
outlet, only the specific quantity of refrigerant, as required for optimum vaporization, is injected.
Fig. 83: Identifying Expansion Valve Components
EXPANSION VALVE, LOCATION - GF83.40-P-2123-02GH
The expansion valve (1) is located on the right at the rear in the engine compartment next to the battery.
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1998-2005 HVAC Climate Control - 163 Chassis
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Fig. 84: Locating Expansion Valve
EXPANSION VALVE, LO CATION/TASK/DESIGN/FUNCTION - GF83.40-P-2123GC
MODEL 163 up to 31.08.01, 168 with CODE (580) Ai r conditioning or Tempmatic for USA
MODEL 163 as of 01.09.01 with CODE (580a) Automatic air conditioning
Design
2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
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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
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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
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opened.
the injected air is dehumidified, Reheat mode
blend air flaps controlled
footwell nozzles closed
DEFROSTER BUTTON, LOCATION / TASK / FUNCTION - GF83.40-P-2139GI
MODEL 163 as of 01.09.01 with CODE (580a) Automatic air conditioning
Fig. 87: Identifying Blower Switch And Defroster Button
BLOWER BUTTON POSITION/TASK/FUNCTION - GF83.40-P-2144GI
MODEL 163 as of 01.09 01 with CODE (580a) Automatic air conditioning in the rear ventilation control
panel
Defroster button,
locationThe defroster button ( ) is located in the center in the upper half of
the blower switch (1) on the AAC push-button control module (N22).
Defroster button,
purposeThe defroster button ( ) starts the defroster function.
Defroster button,
function GF83.40-P-
2139-02GI
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Fig. 88: Identifying Blower Button
RECIRCULATING AIR PUSH-BUTTON, LOCATION/TASK/FUNCTION - GF83.40-P-2145GI
MODEL 163 as of 01.09.01 with CODE (580a) Automatic air conditioning
Fig. 89: Identifying Recirculating Air Push
-button And Blower Switch
AUTO BUTTON, LOCATION / TASK / FUNCTION - GF83.40-P-2147GI
MODEL 163 as of 01.09.01 with CODE (580a) Automatic air conditioning
Blower button,
locationThe blower button ( ) is located in the center in the rear
ventilation control panel.
Blower button,
taskThe blower button ( ) is used to cut in the blower motor for
fresh air and recirculating air operation.
Blower button,
function GF83.40-P-2100-
01GI
Recirculating air
push-button, positionThe recirculating air push-button ( ) is located in the center
in the lower half of the blower switch (1) on the AAC push-
button control module (N22).
Recirculating air
push-button, task
The recirculating air push-button ( ) is used to operate the
fresh air/recirculated air flap to permit air to be directed out of the
vehicle interior.
Function feedback takes place by means of a red LED.
Recirculating air
push-button, function GF83.40-P-
2102-01GI
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1998-2005 HVAC Climate Control - 163 Chassis
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Saturday, October 02, 2010 3:23:16 PMPage 108 © 2006 Mitchell Repair Information Company, LLC.