Page 3425 of 4133
Fig. 151: Identifying Heat Exchanger Components
REPLACE BULBS IN PUSH-BUTTON CONTROL MODULE - AR83.25-P-1123GH
MODELS 163.113/154/174/136/172 up to 31.8.01
Remove/Install
1Remove AC housing AR83.30-P-
5200GH
2Remove bolt (1) from the covering on the
air duct (2)The bolt lies under the air
duct seal.
3Remove lever for blend air flap (3)
4Unscrew bolt (4) at bracket (5).
5Remove heat exchanger (6) upward
6Install in the reverse order
7Inspect cooling system for leaks AR20.00-P-
1010HA
2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
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Page 3426 of 4133
Fig. 152: Identifying Push-button Control Module Components
Commercially available tools
REMOVE AND INSTALL SERIES RESISTOR FOR HEATER BLOWER - AR83.25-P-1250GH
MODEL 163.113 /128 /136 /154 /157 /172 /174 /175
Shown on model 163 up to VIN A289564, X754619
Removal, installation
1Detach rotary knob (3) at push-
button control module (1) Installation: Rotary knob can only be
pushed on the shaft in one position.
2Remove bulb (2) *WH58.30-Z-
1040-02A
3Install in the reverse order
NumberDesignation
WH58.30-Z-1040-02ATweezers, straight 160 mm with rounded tips
2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
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Page 3427 of 4133
Fig. 153: Identifying Series Resistor For Heater Blower Components (Shown On Model 163 Up To VIN
A289564, X754619)
REMOVE/INSTALL COVER AT AIR INTAKE - AR83.25-P-1405GH
MODEL 163.113 /128 /136 /154 /157 /172 /174 /175
Remove/install
1Remove cover below instrument panel (2) (on right)Up to VIN A145272,
X708318.AR68.10-P-
1520GH
As of VINA145273,
X708319.AR68.10-P-
1520GI
2Disconnect connector (4) on blower motor series
resistor group (R14)
3Unscrew screws (3) from blower motor series
resistor group (R14) on heater housing (1)
4Remove blower motor series resistor group (R14)
5Install in the reverse order
2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
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Page 3428 of 4133

Fig. 154: Identifying Components For Cover At Air Intake - Model
163.113 /128 /136 /154 /157 /172 /174 /175
CHECKING AIR CONDITIONING SYSTEM FOR LEAKAGE - AR83.30-D-1209-01A
Workshop equipment
Remove/install
Injury hazard by trapping or crushing, in
extreme cases with loss of limbs when
reaching into windshield wiper mechanismAlways remove ignition key when
working on windshield wiper
mechanism.AS82.30-Z-
0001-01A
1Remove wiper arms (1) AR82.30-P-
6100GH
2Detach rubber seal (2) from firewall
3Remove metal clips (5)
4Unscrew nuts (4) at firewall Remove foam insert.
5Seal off washer fluid hose at check valve
6Remove cover (3) together with water
deflector panel (6)
If damaged, detach water
deflector panel (6) from cover (3).
Installation: Lubricate upper
edge of cover and windshield at
bottom with soapy water.
7Install in the reverse order
2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
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Page 3429 of 4133
1. Start vehicle engine and switch on air conditioning system.
2. Check entire air conditioning circuit using leak detector probe (1).
Remain for some time in areas where leaks are suspected.
Since refrigerant is heavier than air and sinks, always guide leak detector probe (1) underneath the locations
where leaks are suspected.
Line connections, screwed pipe connections, condensers and evaporators are the most frequent cause of
refrigerant leaks.
Fig. 155: Identifying Air Conditioning System Leak Detector Probe
CARRY OUT QUICK TEST ON AIR CONDITIONING SYSTEM - AR83.30-D-1209A
MODEL 163 with CODE (580) Air conditioning or Tempmatic for USA
MODELS 901.0/3 /4, 902.0/3 /4, 903.0/3 /4, 904.0/3 /4 with CODE (H06) Air conditioning
WE58.40-Z-1002-20AAir conditioning leak detector
2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
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Page 3430 of 4133
Fig. 156: Identifying Quick Test On Air Conditioning System - Shown On Models 901, 902, 903, 904
Shown on models 901, 902, 903, 904
Prerequisites for
testing
1Place vehicle with open
windows in the shade
2Set heater control valve
to "cold"
3
Set heating and
ventilation system to
fresh air mode
4
Fully open lateral
nozzles, center nozzles
and footwell flaps
5Start vehicle engine and
allow to idle
Inspecting
6Switch air conditioning
on
When the air conditioning is switched on, the vehicle
engine's idle speed must increase. No idle speed increase ?
Check function of refrigerant compressor RPM sensor in the
event of complaint ?
2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
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Page 3431 of 4133

Commercially available tools
Workshop equipment
DRAINING, EVACUATING AND REFILLING AIR CONDITIONING, CHECKING FUNCTION AND CHECKING FOR
LEAKS - AR83.30-P-1760GH
MODELS 163.113 /128 /136 /154 /157 /172 /174 /175 with CODE (580) Air conditioning or Tempmatic for
USA
Replace refrigerant compressor RPM sensor
Models 901-904
Not in model 163AR83.55-D-
5320A
7
Set blower rotary
switch to maximum
blower setting
8Check that refrigerant
flows free of bubbles
If the system is filled sufficiently, the refrigerant must flow
through the inspection glass (2) free of bubbles. A newly-
filled system may initially reveal bubbles. In this case, wait
for approx. 10 min. and check inspection glass again.
Does not reveal bubble-free flow ?
Check entire air conditioning circuit for leaks using leak
detector (3).AR83.30-D-
1209-01A
Air conditioning system leak detector*WE58.40-Z-
1002-20A
9Determine air outlet
temperature
Switch blower rotary switch to stage "1".
Insert sensor of temperature measurement device (1) into the
air outlet of the center nozzles.
After running for a period of 5 min., the air outlet temperature
must not be less than 2°C and more than 12°C. After 5 min., at
the latest, the refrigerant compressor must also be connected
and disconnected.
If the refrigerant compressor is disconnected at below 2°C ?
Check evaporator temperature switch. If the air outlet
temperature is not achieved ?
Check the connection and disconnection of the refrigerant
compressor or the refrigerant pressure upstream and
downstream of the refrigerant compressor.
*WH58.30-Z-
1005-08A
10
Switch air conditioning
off and shut vehicle
engine off
NumberDesignation
WH58.30-Z-1005-08ATemperature measuring device
WE58.40-Z-1002-20AAir conditioning leak detector
2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
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Page 3432 of 4133

Fig. 157: Checking Draining, Evacuating And Refilling Air Conditioning Function
Draining
Risk of explosion from welding or
soldering work on closed air conditioning
system. Risk of poisoning . Inhaling
overheated refrigerant vapors may be
toxic. Risk of injury from skin and eye
contact with liquid refrigerant.
Do not carry out any welding work on the
closed air conditioning system or in the
surrounding area. No smoking or open flames.
Wear eye protection and protective gloves.
Work only in well ventilated areas. Carry out
repair work on the air conditioning system
circuit only after the system has been
discharged.
AS83.00-Z-
0001-01A
1
Connect the connector (blue) (3) of the
filling unit (1) to the Schrader valve of
the high-pressure line and the connector
(red) (2) to the Schrader valve of the
suction line.
During all steps, the operating instructions
for the particular filling unit must be
followed.
*WE58.40-
Z-1002-22A
2Discharge air conditioning system
3
Drain separated oil for refrigerant
compressor out of the inspection glass for
the filling unit and determine the quantity
exactly
Drained quantity must be replaced by fresh
oil for refrigerant compressor.
Evacuate
Clean air conditioning system and
2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
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