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  
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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  
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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  
Saturday, October 02, 2010 3:23:18 PMPage 188 © 2006 Mitchell Repair Information Company, LLC.