Mercedes-Benz | 2001 C 320 | Specifications | Mercedes-Benz 2001 C 320 Specifications

2001 Mercedes-Benz ML320
2000-01 MANUAL A/C-HEATER SYSTEMS ML 320, ML 430 & ML 55
2000-01 MANUAL A/C-HEATER SYSTEMS
ML 320, ML 430 & ML 55
SPECIFICATIONS
SPECIFICATIONS
Application
Compressor Type
Specification
Nippondenso 7SB16 7-Cyl.
(1)
Compressor Belt Tension
(2) 5.6-6.3 ozs.
Compressor Oil Capacity
Refrigerant (R-134a) Capacity
26.4 ozs.
System Operating Pressures
(1) Belt tension is automatically adjusted by belt tensioner.
(3)
(2) Use Densooil 8 (A 001 989 08 03).
(3) Information is not available from manufacturer.
DESCRIPTION & OPERATION
WARNING: To avoid injury from Accidental air bag deployment, read and carefully
follow all SERVICE PRECAUTIONS and DISABLING & ACTIVATING AIR
BAG SYSTEM procedures in AIR BAG SYSTEM SAFETY article in
GENERAL SERVICING.
A/C CONTROL PANEL
The A/C control panel contains switches to control A/C functions such as blower motor speed, mode control,
in-vehicle temperature, A/C on/off, and fresh/recirculated air control. See Fig. 1 .
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© 2006 Mitchell Repair Information Company, LLC.
2001 Mercedes-Benz ML320
2000-01 MANUAL A/C-HEATER SYSTEMS ML 320, ML 430 & ML 55
Fig. 1: Identifying A/C Control Panel Functions
Courtesy of MERCEDES-BENZ OF NORTH AMERICA
BLOWER MOTOR KNOB
Located in the A/C control panel, the blower motor knob controls blower motor speed in 4 settings. See Fig. 1 .
The blower motor knob sends a voltage signal through the blower motor resistor in "1" to "3" positions and bypasses blower motor resistor in position No. 4. See WIRING DIAGRAMS . Setting blower motor knob to "0"
position will turn system off.
MODE CONTROL KNOB
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© 2006 Mitchell Repair Information Company, LLC.
2001 Mercedes-Benz ML320
2000-01 MANUAL A/C-HEATER SYSTEMS ML 320, ML 430 & ML 55
Mode control knob controls air distribution throughout the passenger compartment. Air distribution doors are
controlled by cables activated by the mode control knob. See Fig. 1 . Four mode positions are available with
detents in-between to adjust airflow for personal comfort.
Defrost
Set mode control knob to 12-o'clock position. Air will exit from defrost outlets and side window vents.
Vent
Set mode control knob to 9-o'clock position. Air will exit from instrument panel outlets.
Floor
Set mode control knob to 6-o'clock position. Air will exit from floor outlets.
Blend/Bi-Level
Set mode control knob to 3-o'clock position. Air will exit from defrost, instrument panel, and floor outlets.
TEMPERATURE CONTROL KNOB
Air temperature is controlled by a variable resistor rotary control switch. See Fig. 1 . Switch receives voltage
signal and depending upon position, controls voltage signal sent to air mix damper door motor. See Fig. 2 .
Voltage controls position of motor for heating and cooling.
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© 2006 Mitchell Repair Information Company, LLC.
2001 Mercedes-Benz ML320
2000-01 MANUAL A/C-HEATER SYSTEMS ML 320, ML 430 & ML 55
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© 2006 Mitchell Repair Information Company, LLC.
2001 Mercedes-Benz ML320
2000-01 MANUAL A/C-HEATER SYSTEMS ML 320, ML 430 & ML 55
Fig. 2: Locating Climate Control Components
Courtesy of MERCEDES-BENZ OF NORTH AMERICA
FRESH/RECIRCULATION SWITCH
Fresh/recirculation switch controls voltage signal to fresh air recirculation door motor. See Fig. 1 and Fig. 2 .
With switch indicator light on, air will recirculate. With switch indicator light off, air will enter from outside of
vehicle.
A/C CONTROL MODULE
The A/C control module (A/C amplifier) is the control unit for the A/C system. See Fig. 2 . The module
receives inputs from various sensors and processes the information to control various outputs for the A/C
system for optimal control.
The A/C control module inputs are as follows:






A/C Switch
In-Vehicle Air Temperature Sensor
Temperature Selector Knob
Blower Motor Knob
Evaporator Temperature Sensor
Air Mix Damper Door Position Sensor
The A/C control module output functions are as follows:



Air Mix Damper Door Motor
All Activity Module
Fresh/Recirculation Door Motor
ALL ACTIVITY MODULE
All Activity Module (AAM) receives inputs to determine if specified conditions have been met to allow
operation of A/C-heater system. If conditions are met, the AAM will send signals to the A/C compressor,
condenser fans relay and the blower motor relay to command or enable operation.
IN-VEHICLE TEMPERATURE SENSOR
The in-vehicle temperature sensor is a negative temperature coefficient resistor. Sensor sends signals to the A/C
control module to maintain in-vehicle temperature. Sensor is located on the center panel of the instrument
cluster.
DUST FILTER
A dust filter provides filtering of air entering or recirculating in the passenger's compartment. The dust filter is
mounted between blower motor and evaporator, below passenger's side of instrument panel, to left of blower
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© 2006 Mitchell Repair Information Company, LLC.
2001 Mercedes-Benz ML320
2000-01 MANUAL A/C-HEATER SYSTEMS ML 320, ML 430 & ML 55
motor. See Fig. 2 .
PROGRAMMING
RECODING RADIO
CAUTION: Before disconnecting battery, obtain 5-digit radio security code from
vehicle owner. Radio will be disabled until properly recoded.
NOTE:
Radio will not operate if power supply to radio is interrupted. Obtain 5-digit
radio security code from vehicle owner before disconnecting battery.
1. Turn ignition on. Ensure CODE is displayed on radio display. Enter code numbers using radio station
buttons. For example, use station button No. 1 for code No. 1 and so on.
2. After first number is entered, CODE disappears and number entered is displayed followed by 4 dashes.
After entering 5-digits, confirm correct security code has been entered. If incorrect code has been entered,
entire code must be reentered.
3. Confirm entry of correct security code using "<" (less than) or ">" (more than) buttons. If an incorrect
code is entered, CODE will be displayed on radio display. If security code is entered incorrectly 3 times,
WAIT will be displayed and radio will be disabled for about 10 minutes.
4. If, after 3 more attempts, correct security code has not been entered, radio will be disabled for 60 minutes.
Radio disable time runs down only when radio is turned off.
VERSION CODING
Version coding is performed using a Mercedes-Benz Hand-Held Tester (HHT) and is on-screen menu guided.
After connecting HHT to DLC, vehicle communication is possible as soon as ignition key is inserted into
ignition switch (position of switch does not matter). Version coding menu, position 1, is reached via main menu
and control module adaptation, position 5. There are 2 possible version codings available: readout of version
code and transfer to new control module or readout of version code and to alter code.
To access A/C system version coding, position 2 must be selected and then position 7 for A/C system. Two
selections can be used: A/C system is installed or A/C system is not installed.
SELF-DIAGNOSTICS
RETRIEVING & ERASING DIAGNOSTIC TROUBLE CODES
Retrieving and erasing of Diagnostic Trouble Codes (DTC) must be performed using Mercedes-Benz HandHeld Tester (HHT). See HHT instructions for retrieving A/C-heater system related DTC. After noting codes,
see CLIMATE CONTROL DTC table. To erase DTC, follow HHT instructions.
When retrieving DTC from A/C push button control module, short and open circuits cannot be differentiated
from each other in every instance. When accessing DTC from any control module memory, all stored DTC are
shown. As a result, some DTC shown will not apply to climate control system.
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© 2006 Mitchell Repair Information Company, LLC.
2001 Mercedes-Benz ML320
2000-01 MANUAL A/C-HEATER SYSTEMS ML 320, ML 430 & ML 55
CLIMATE CONTROL DTC
DTC
B1232
Possible Cause
(1) Refrigerant Pressure Sensor
B1419
Electromagnetic Clutch
(1) Check A/C refrigerant pressure sensor. See A/C REFRIGERANT PRESSURE SWITCH under
ELECTRICAL TESTS.
SYSTEM TESTS
WARNING: To avoid injury from Accidental air bag deployment, read and carefully
follow all SERVICE PRECAUTIONS and DISABLING & ACTIVATING AIR
BAG SYSTEM procedures in AIR BAG SYSTEM SAFETY article in
GENERAL SERVICING.
CONNECTING TEST EQUIPMENT
Remove radio to gain access to A/C push button control unit harness connector. Turn ignition off. Disconnect
control unit harness connector. Connect socket box Test Cable (163 589 01 63 00) to A/C push button control
unit and wiring harness. See Fig. 3 . Connect test cable to Socket Box (124 589 00 21 00). Connect test
equipment leads to socket box terminals as instructed in circuit tests.
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© 2006 Mitchell Repair Information Company, LLC.
2001 Mercedes-Benz ML320
2000-01 MANUAL A/C-HEATER SYSTEMS ML 320, ML 430 & ML 55
Fig. 3: Connecting Test Cable & Socket Box To A/C Push-Button Control Unit
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.
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© 2006 Mitchell Repair Information Company, LLC.
2001 Mercedes-Benz ML320
2000-01 MANUAL A/C-HEATER SYSTEMS ML 320, ML 430 & ML 55
FUNCTIONAL TEST PREPARATION
1. Check condition of fuses F16, F41, F43 and F44. See WIRING DIAGRAMS . Repair and/or replace
fuses and necessary.
2. Turn ignition on. Locate in-vehicle temperature sensor aspirator blower vent grille above anti-theft
indicator light. Place a half-inch square of tissue paper over aspirator blower vent grille. If paper stays on
vent grille, go to next step. If paper does not stay on vent grille, correct insufficient aspirator blower
ventilation.
3. Put shift lever in "P" and engage parking brake. Run engine at idle until it reaches normal operating
temperature, about 176°F (80°C). Ensure ambient (outside) temperature is greater than 58°F (15°C).
4. Manually open center and side air outlets. Ensure recirculation button is not depressed. Set blower speed
knob to position No. 1.
FUNCTION TEST
NOTE:
Function test steps must be performed in order given.
Defrost Mode
To check operation in defrost mode, set temperature selector knob to White range (vertical). Set mode control
knob to 12-o'clock position (vertical). Ensure A/C button indicator is illuminated. Air will vent from defrost and
center outlets and A/C compressor will engage. If operation is not as specified, perform the following in order:












Check voltage supply circuit Z50/2 between No. 16 fuse (15-amp) and connected components. See
VOLTAGE SUPPLY CIRCUIT Z50/2 under ELECTRICAL TESTS.
Check ground circuit. See GROUND CIRCUIT Z50/4 under ELECTRICAL TESTS.
Check in-vehicle temperature sensor signal voltage. See IN-VEHICLE TEMPERATURE SENSOR
under ELECTRICAL TESTS.
Check in-vehicle temperature sensor signal resistance. See IN-VEHICLE TEMPERATURE SENSOR
under ELECTRICAL TESTS.
Check icing protection temperature sensor signal voltage. See ICING PROTECTION
TEMPERATURE SENSOR under ELECTRICAL TESTS.
Check icing protection temperature sensor resistance. See ICING PROTECTION TEMPERATURE
SENSOR under ELECTRICAL TESTS.
Check activation voltage during temperature reduction. See ACTIVATION VOLTAGE
TEMPERATURE under ELECTRICAL TESTS.
Check activation voltage during temperature increase. See ACTIVATION VOLTAGE
TEMPERATURE under ELECTRICAL TESTS.
Check blend air flap actuator motor operation voltage. See BLEND AIR FLAP ACTUATOR MOTOR
under ELECTRICAL TESTS.
Check blend air flap actuator motor resistance. See BLEND AIR FLAP ACTUATOR MOTOR under
ELECTRICAL TESTS.
Check A/C button activation. See A/C BUTTON under ELECTRICAL TESTS.
Check A/C pressure switch. See A/C REFRIGERANT PRESSURE SWITCH under ELECTRICAL
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© 2006 Mitchell Repair Information Company, LLC.
2001 Mercedes-Benz ML320
2000-01 MANUAL A/C-HEATER SYSTEMS ML 320, ML 430 & ML 55
TESTS.
Normal Ventilation In Regulating Mode
To check normal ventilation in regulating mode, set temperature selector knob to White range (vertical). Set
mode control knob to 4-o'clock position. Ensure A/C button indicator is illuminated. Air will vent from upper
and lower outlets and A/C compressor will engage. Ambient air will flow from center outlet and coolant
circulation pump will operate. If operation is not as specified, perform the following in order:


Check A/C button activation. See A/C BUTTON under ELECTRICAL TESTS.
Check A/C pressure switch. See A/C REFRIGERANT PRESSURE SWITCH under ELECTRICAL
TESTS.
Economy Setting Not In Heating Mode
To check economy setting without heating mode activated, set temperature selector knob to Blue range. Set
mode control knob to the 9-o'clock position. Ensure A/C button indicator is not illuminated. Ambient air will
flow from center outlet and A/C compressor will NOT be engaged. If operation is not as specified, perform the
following:

Check A/C button activation. See A/C BUTTON under ELECTRICAL TESTS.
Economy Setting In Heating Mode
To check economy setting with heating mode activated, set temperature selector knob to Red range. Set mode
control knob to the 4-o'clock position. Ensure A/C button indicator is not illuminated. Heated air will flow from
lower, upper and center outlets and A/C compressor will NOT be engaged. If operation is not as specified,
perform the following:

Check A/C button activation. See A/C BUTTON under ELECTRICAL TESTS.
Recirculation Mode
To check recirculation mode, press fresh/recirculation button. Ensure fresh/recirculation indicator is
illuminated. Set blower speed knob to position No. 4. Blower fan noise will increase noticeably. If operation is
not as specified, check wiring between recirculated air flap element, heater-A/C switch and No. 16 fuse (15amp).
ELECTRICAL TESTS
Voltage Supply Circuit Z50/2
1. Connect socket box to A/C push button control unit and wiring harness. See CONNECTING TEST
EQUIPMENT . Turn ignition on, with engine off. Connect voltmeter positive lead to socket box terminal
No. 7 and negative lead to terminal No. 9.
2. Voltage should be 11-14 volts. If voltage is not as specified, check voltage supply circuit Z50/2 between
No. 16 fuse (15-amp) and connected components. See WIRING DIAGRAMS . Repair as necessary.
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© 2006 Mitchell Repair Information Company, LLC.
2001 Mercedes-Benz ML320
2000-01 MANUAL A/C-HEATER SYSTEMS ML 320, ML 430 & ML 55
Ground Circuit Z50/4
1. Connect socket box to A/C push button control unit wiring harness connector. See CONNECTING
TEST EQUIPMENT . Turn ignition off. Ensure A/C push button control unit is not connected to socket
box.
2. Connect ohmmeter positive lead to socket box terminal No. 9 and negative lead to body ground.
Resistance should be zero. If resistance is not as specified, check control unit ground circuit Z50/4. See
WIRING DIAGRAMS . Repair as necessary.
In-Vehicle Temperature Sensor
1. Connect socket box to A/C push button control unit and wiring harness. See CONNECTING TEST
EQUIPMENT . Connect voltmeter positive lead to socket box terminal No. 12 and negative lead to
terminal No. 9.
2. Turn ignition on. Turn temperature control knob to Red range detent. Voltage should be 1.9 volts at 68°F
(20°C). If voltage is as specified, go to next step. If voltage is not as specified, check in-vehicle
temperature sensor circuits. See WIRING DIAGRAMS . Repair as necessary. If circuits are okay,
replace in-vehicle temperature sensor.
3. Turn ignition off. Disconnect test cable from A/C push button control unit. Connect ohmmeter positive
lead to socket box terminal No. 2 and negative lead to terminal No. 12. Measure temperature sensor
resistance at specified temperatures. See IN-VEHICLE TEMPERATURE SENSOR RESISTANCE
table.
4. If resistance is not as specified, check wiring harness and connectors between A/C push button control
unit, in-vehicle temperature sensor, blend air flap actuator position sensor and temperature regulator
switch. Repair as necessary.
IN-VEHICLE TEMPERATURE SENSOR RESISTANCE
Sensor Temperature - °F (°C)
68 (20)
77 (25)
104 (40)
Ohms
2100
1700
900
Icing Protection Temperature Sensor
1. Connect socket box to A/C push button control unit and wiring harness. See CONNECTING TEST
EQUIPMENT . Connect voltmeter positive lead to socket box terminal No. 11 and negative lead to
terminal No. 9.
2. Turn ignition on. Voltage should be 2.0-2.4 volts at 32°F (0°C) and 1.4-1.8 volts at 59°F (15°C). If
voltage is as specified, go to next step. If voltage is not as specified, check icing protection temperature
sensor circuits. See WIRING DIAGRAMS . Repair as necessary. If circuits are okay, replace icing
protection temperature sensor.
3. Turn ignition off. Disconnect test cable from A/C push button control unit. Connect ohmmeter positive
lead to socket box terminal No. 3 and negative lead to terminal No. 11. Measure temperature sensor
resistance at specified temperatures. See ICING PROTECTION TEMPERATURE SENSOR
RESISTANCE table.
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© 2006 Mitchell Repair Information Company, LLC.
2001 Mercedes-Benz ML320
2000-01 MANUAL A/C-HEATER SYSTEMS ML 320, ML 430 & ML 55
4. If resistance is not as specified, check wiring harness between temperature sensor and control unit. Repair
as necessary. If wiring harness is okay, replace icing protection temperature sensor.
ICING PROTECTION TEMPERATURE SENSOR RESISTANCE
Sensor Temperature - °F (°C)
43 (6)
59 (15)
72 (22)
77 (25)
Ohms
3600
2300
1700
1500
Activation Voltage Temperature
1. Connect socket box to A/C push button control unit and wiring harness. See CONNECTING TEST
EQUIPMENT . Connect voltmeter positive lead to socket box terminal No. 2 and negative lead to
terminal No. 9.
2. Turn ignition on. Turn temperature control knob to Blue range detent. Voltage should be more than 2.0
volts. Turn temperature control knob from Blue range detent to Red range detent. Voltage should be more
than 3.0 volts.
3. If voltage is as specified, go to next step. If voltage is not as specified, check recirculated air switch
circuits. See WIRING DIAGRAMS . Repair as necessary. If circuits are okay, replace recirculated air
switch.
4. Connect voltmeter positive lead to socket box terminal No. 5 and negative lead to terminal No. 9. Turn
ignition on. Turn temperature control knob to Blue range detent. Voltage should be more than 3.0 volts.
Turn temperature control knob from Blue range detent to Red range detent. Voltage should be more than
4.0 volts.
5. If voltage is not as specified, check recirculated air switch circuits. See WIRING DIAGRAMS . Repair
as necessary. If circuits are okay, replace recirculated air switch.
Blend Air Flap Actuator Motor
1. Connect socket box to A/C push button control unit and wiring harness. See CONNECTING TEST
EQUIPMENT . Connect voltmeter positive lead to socket box terminal No. 1 and negative lead to
terminal No. 9.
2. Turn ignition on. Turn temperature control knob to Blue range detent. Voltage should be less than one
volt. Turn temperature control knob from Blue range detent to Red range detent. Voltage should be 11.014.0 volts.
3. If voltage is as specified, go to next step. If voltage is not as specified, check blend air flap actuator motor
wiring harness circuits. See WIRING DIAGRAMS . Repair as necessary. If circuits are okay, replace
blend air flap actuator motor.
4. Connect voltmeter positive lead to socket box terminal No. 8 and negative lead to terminal No. 9. Turn
ignition on. Turn temperature control knob to Red range detent. Voltage should be less than one volt.
Turn temperature control knob from Red range detent to Blue range detent. Voltage should be 11.0-14.0
volts.
5. If voltage is as specified, go to next step. If voltage is not as specified, check blend air flap actuator motor
wiring harness circuits. See WIRING DIAGRAMS . Repair as necessary. If circuits are okay, replace
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© 2006 Mitchell Repair Information Company, LLC.
2001 Mercedes-Benz ML320
2000-01 MANUAL A/C-HEATER SYSTEMS ML 320, ML 430 & ML 55
blend air flap actuator motor.
6. Turn ignition off. Disconnect test cable from A/C push button control unit. Connect ohmmeter positive
lead to socket box terminal No. 1 and negative lead to terminal No. 8. Resistance should be 120 ohms.
7. If resistance is not as specified, check blend air flap actuator motor circuits. See WIRING DIAGRAMS .
Repair as necessary. If circuits are okay, replace blend air flap actuator motor.
A/C Button
1. Connect socket box to A/C push button control unit and wiring harness. See CONNECTING TEST
EQUIPMENT . Connect voltmeter positive lead to socket box terminal No. 10 and negative lead to
terminal No. 9.
2. Turn ignition on. Depress A/C button switch to on position and set blower speed knob to position No. 4.
Ensure A/C button indicator is illuminated. Voltage should be less than one volt. Depress A/C button
switch to off position with A/C button indicator not illuminated or set blower speed knob to off position.
Voltage should be 11-14 volts.
3. If voltage is as specified, go to next step. If voltage is not as specified, check A/C button wiring harness
circuits. See WIRING DIAGRAMS . Repair as necessary. If circuits are okay, replace A/C button
switch.
4. Turn ignition on. Depress A/C button switch to on position and set blower speed knob to position No. 4.
Ensure A/C button indicator is illuminated. Connect voltmeter positive lead to socket box terminal No. 4
and negative lead to terminal No. 9. Voltage should be more than 3.0 volts.
5. Connect Fused Jumper Wire (124 589 37 63 00) between socket box terminals No. 4 and 11. Depress A/C
button switch to on position and set blower speed knob to position No. 4. Ensure A/C button indicator is
illuminated. Measure voltage. Voltage should be less than one volt.
6. If voltage is not as specified, check A/C button wiring harness circuits. See WIRING DIAGRAMS .
Repair as necessary. If circuits are okay, replace A/C button switch.
A/C Refrigerant Pressure Switch
1. Turn ignition off. Disconnect refrigerant pressure sensor connector. Turn ignition on. Connect voltmeter
positive lead to pressure sensor harness connector terminal "B" (Pink wire) and negative lead to terminal
"A" (Tan wire). Voltage should be 4.75-5.25 volts.
2. If voltage is as specified, replace A/C refrigerant pressure sensor. If voltage is not as specified, check
wiring harness between refrigerant pressure sensor and All Activity Module (AAM). See WIRING
DIAGRAMS . Repair as necessary. If circuits are okay, replace AAM and retest A/C system.
Outside Temperature Sensor
1. Connect socket box to A/C push button control unit and wiring harness. See CONNECTING TEST
EQUIPMENT . Turn ignition off. Connect ohmmeter positive lead to socket box terminal No. 12 and
negative lead to terminal No. 3.
2. Disconnect test cable from A/C push button control unit. See OUTSIDE TEMPERATURE SENSOR
RESISTANCE table. If resistance is not as specified, check wiring harness between outside temperature
sensor and A/C push button control unit. See WIRING DIAGRAMS . Repair as necessary. If wiring
harness is okay, replace outside temperature sensor.
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© 2006 Mitchell Repair Information Company, LLC.
2001 Mercedes-Benz ML320
2000-01 MANUAL A/C-HEATER SYSTEMS ML 320, ML 430 & ML 55
OUTSIDE TEMPERATURE SENSOR RESISTANCE
Sensor Temperature - °F (°C)
68 (20)
77 (25)
104 (40)
122 (50)
Ohms
2100
1700
900
600
READING ACTUAL VALUES WITH HHT
Connect Hand-Held Tester (HHT) to DLC and follow displayed procedures. Actual values displayed on HHT
show normal operation value of A/C systems or components. See ACTUAL VALUES table. If value is not as
specified, check system or components in order. Repair as necessary.
ACTUAL VALUES
Step (1)
01
02
03
04
05
08
Test Condition
Value
System/Component
.....
11-14 Volts
Engine Operating At
Normal Temperature
Ignition ON
About 176°F (80°C)
Ignition ON
ON/OFF
Ambient Air Temperature
About 68°F (20°C)
Ignition ON, Blower At
ON/OFF
Stage 4
Ignition ON
ON/OFF
09
Engine On, A/C Indicator Refrigerant Pressure At
On, Blower Motor At
174 psi (12 bar)
Stage 4
10
Engine On, A/C Indicator
ON/OFF
On, Blower Motor At
Stage 4
11
Ignition ON, Activate
YES/NO
A/C System
(1) Step numbers not shown are not used.
Voltage Supply Wiring (Circuit
No. 30) & Battery
Wiring, ECT Sensor & AAM
Wiring, Outside Temperature
Sensor & AAM
Wiring, Blower Motor Relay,
Blower Motor & AAM
Wiring, Engine Cooling Fan
Stage 1, Aux. Fan & AAM
Wiring, Coolant Circulation Pump
Relay, Coolant Circulation Pump
& AAM
(2) Refrigerant Pressure Sensor
(3) AAM, A/C Compressor
Wiring, A/C Push Button Control
Module, AAM
(2) Check A/C refrigerant pressure switch. See A/C REFRIGERANT PRESSURE SWITCH under
ELECTRICAL TESTS.
(3) Check A/C button activation. See A/C BUTTON under ELECTRICAL TESTS.
REMOVAL & INSTALLATION
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© 2006 Mitchell Repair Information Company, LLC.
2001 Mercedes-Benz ML320
2000-01 MANUAL A/C-HEATER SYSTEMS ML 320, ML 430 & ML 55
WARNING: To avoid injury from accidental air bag deployment, read and carefully
follow all SERVICE PRECAUTIONS and DISABLING & ACTIVATING AIR
BAG SYSTEM procedures in AIR BAG SYSTEM SAFETY article in
GENERAL SERVICING.
CAUTION: Before disconnecting battery, obtain 5-digit radio security code from
vehicle owner. Radio will be disabled until properly recoded.
A/C EVAPORATOR HOUSING UNIT
Removal & Installation
1. Drain engine coolant. Remove coolant expansion reservoir nuts, disconnect hoses and remove reservoir.
Discharge A/C system, using approved refrigerant recovery/recycling equipment.
2. Remove expansion valve self-locking nut and discard. See Fig. 5 . Disconnect refrigerant lines from
expansion valve. Plug exposed refrigerant lines to protect A/C system from moisture and debris.
3. Remove instrument panel. See INSTRUMENT PANEL . Remove Electronic Transmission Control
(ETC) module. See Fig. 4 . Disconnect air mix flap actuator connector.
4. Disconnect recirculated air flap element. Disconnect evaporator temperature sensor. Disconnect blower
motor resistor and blower motor connectors. Remove A/C push button control module. Release wiring
harness.
5. Remove insulating mat. See Fig. 5 . Disconnect water drain hose from bottom of A/C housing. Release
A/C housing-to-air distributor clips and remove A/C housing upward. To install, reverse removal
procedure. Recode radio. See RECODING RADIO under PROGRAMMING.
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© 2006 Mitchell Repair Information Company, LLC.
2001 Mercedes-Benz ML320
2000-01 MANUAL A/C-HEATER SYSTEMS ML 320, ML 430 & ML 55
Fig. 4: Removing Evaporator Housing Unit
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.
A/C MIX FLAP ACTUATOR
Removal & Installation
Remove instrument panel. See INSTRUMENT PANEL . Disconnect air mix flap actuator connector. Remove
3 screws and remove air mix flap actuator. To install reverse removal procedure.
A/C PUSH BUTTON CONTROL MODULE
Removal & Installation
Disconnect negative battery cable. Remove A/C push button control panel. See A/C PUSH BUTTON
CONTROL PANEL . Remove 4 A/C push button control module screws and remove control module from
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© 2006 Mitchell Repair Information Company, LLC.
2001 Mercedes-Benz ML320
2000-01 MANUAL A/C-HEATER SYSTEMS ML 320, ML 430 & ML 55
A/C housing. Disconnect control module connector. To install reverse removal procedure. Recode 5-digit radio
security code. Using HHT, check for DTC and erase, and set clock.
A/C PUSH BUTTON CONTROL PANEL
Removal & Installation
1. Obtain 5-digit radio security code from vehicle owner. Disconnect negative battery cable. Using radio
removal plates, remove radio. Disconnect electrical connectors.
2. Remove instrument panel center section. Remove 4 A/C control panel screws and remove control panel.
Release pull cables and disconnect connectors. To install, reverse removal procedure. Recode radio. See
RECODING RADIO under PROGRAMMING.
BLOWER MOTOR
Removal & Installation
Remove passenger-side instrument panel under cover. Remove blower motor mounting screws from A/C
housing unit. Disconnect blower motor connector and remove blower motor. To install, reverse removal
procedure.
COMPRESSOR
NOTE:
Each time A/C compressor is removed and installed, receiver-drier must be
replaced.
Removal & Installation
1. Discharge A/C system, using approved refrigerant recovery/recycling equipment. Remove accessory
drive belt. Disconnect low pressure refrigerant line from compressor. Discard "O" rings. Plug exposed
openings to protect A/C system from debris and moisture.
2. Disconnect high pressure refrigerant line from compressor. Discard "O" rings. Plug exposed openings to
protect A/C system from debris and moisture. Disconnect electrical connector. Remove compressor
mounting bolts.
3. Raise and support vehicle. Remove compressor from under vehicle without spilling refrigerant oil. To
install, reverse removal procedure. Ensure refrigerant oil quantity in compressor is correct. See
COMPRESSOR REFRIGERANT OIL CHECKING under GENERAL SERVICING. Tighten bolts to
specification. See TORQUE SPECIFICATIONS .
CONDENSER
Removal & Installation
1. Discharge A/C system, using approved refrigerant recovery/recycling equipment. Remove cooling fans.
See COOLING FANS . Disconnect refrigerant line from receiver-drier. See Fig. 5 . Discard "O" rings.
2. Plug exposed openings to protect A/C system from debris and moisture. Remove refrigerant line from
condenser. Remove radiator upper rubber seal. See Fig. 6 . Remove condenser upper mounting screws.
Lift condenser upward and remove.
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© 2006 Mitchell Repair Information Company, LLC.
2001 Mercedes-Benz ML320
2000-01 MANUAL A/C-HEATER SYSTEMS ML 320, ML 430 & ML 55
3. To install, reverse removal procedure. Use NEW "O" rings lubricated with refrigerant oil. If installing a
new or repaired condenser, add 0.68 ounce of NEW refrigerant oil to condenser. Tighten refrigerant line
bolts to specification. See TORQUE SPECIFICATIONS .
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© 2006 Mitchell Repair Information Company, LLC.
2001 Mercedes-Benz ML320
2000-01 MANUAL A/C-HEATER SYSTEMS ML 320, ML 430 & ML 55
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© 2006 Mitchell Repair Information Company, LLC.
2001 Mercedes-Benz ML320
2000-01 MANUAL A/C-HEATER SYSTEMS ML 320, ML 430 & ML 55
Fig. 5: Locating A/C Refrigerant System Components
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.
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© 2006 Mitchell Repair Information Company, LLC.
2001 Mercedes-Benz ML320
2000-01 MANUAL A/C-HEATER SYSTEMS ML 320, ML 430 & ML 55
Fig. 6: Removing Cooling Fans & Condenser
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.
COOLING FANS
Removal & Installation
Remove headlight units. Remove upper frame crossmember, release hood release control cable and remove
crossmember. See Fig. 6 . Remove 2 cooling fans frame bolts on radiator. Disconnect cooling fan connector.
Release outside temperature sensor wiring harness. Pull up on cooling fan and remove. To install, reverse
removal procedure. Ensure cooling fan bottom guides are properly seated in lower mounts.
EVAPORATOR
Removal & Installation
Remove A/C housing unit. See A/C HOUSING UNIT . Remove expansion valve. See Fig. 5 . Discard "O"
rings. Disassemble A/C housing unit. Remove evaporator. Remove evaporator temperature sensor. To install,
reverse removal procedure. Use NEW "O" rings lubricated with refrigerant oil. If installing a new or repair
evaporator, add 1.35 ounces of NEW refrigerant oil to evaporator.
EXPANSION VALVE
Removal & Installation
1. Discharge A/C system, using approved refrigerant recovery/recycling equipment. Without disconnecting
coolant hoses, remove coolant expansion reservoir and set aside. Remove refrigerant line bracket and
loosen clamps. See Fig. 5 . Pull refrigerant lines out of expansion valve.
2. Remove expansion valve self-locking nut and discard. Remove expansion valve. Discard "O" rings. To
install, reverse removal procedure. Use NEW "O" rings lubricated with refrigerant oil. Tighten NEW selflocking nut to specification. See TORQUE SPECIFICATIONS .
INSTRUMENT PANEL & INSTRUMENT PANEL CARRIER
Removal & Installation
1. Secure vehicle against rolling. Set transmission selector to "D" position. Obtain radio security code.
Disconnect negative battery cable. Remove driver-side air bag.
2. Place match marks on steering wheel and steering shaft. Remove steering wheel, upper steering column
covers and combination switch. Remove instrument cluster cover frame. Remove one instrument panel
lower section bolt.
3. Remove screws in footwell from left side of instrument panel bottom section. Remove instrument panel
center section. Remove 4 A/C control panel screws and remove control panel. See Fig. 1 . Release pull
cables and disconnect connectors.
4. Remove screws from center section. Remove glove box. Remove screws in footwell from right side of
instrument panel bottom section. Remove entry courtesy lights. Remove end covers and screws.
5. Release 4 "A" clips between instrument panel bottom section and upper section. See Fig. 7 . Release
parking brake release cable from handle. With assistance, remove instrument panel bottom section.
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© 2006 Mitchell Repair Information Company, LLC.
2001 Mercedes-Benz ML320
2000-01 MANUAL A/C-HEATER SYSTEMS ML 320, ML 430 & ML 55
6. Remove A-pillar panel trim. Remove instrument cluster. Remove defroster vent cover. Remove air vents
and side air nozzles. With assistance, remove upper instrument panel.
7. Remove passenger-side air bag. Remove right side lower instrument panel cover. Remove instrument
panel carrier screws from A/C housing unit. Remove left side lower instrument panel cover.
8. Remove insulating mat between steering column and instrument panel carrier. Remove steering column
bolts and nuts from instrument panel carrier. See Fig. 8 . Remove instrument panel carrier center tunnel
bolts. Disconnect steering column connectors.
9. Remove wiring harness from instrument panel carrier. Remove wiper washer system. Remove instrument
panel carrier nuts from engine compartment side of firewall.
10. Remove A-pillar bolt covers and remove instrument panel carrier A-pillar bolts. With assistance, remove
instrument panel carrier through passenger door. To install, reverse removal procedure.
11. Ensure instrument panel bottom section guide tongues "B" are seated into instrument panel upper section
mounts. See Fig. 8 . Tighten nuts and bolts to specification. See TORQUE SPECIFICATIONS .
Recode radio. See RECODING RADIO under PROGRAMMING.
Fig. 7: Removing Instrument Panel Bottom Section
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.
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© 2006 Mitchell Repair Information Company, LLC.
2001 Mercedes-Benz ML320
2000-01 MANUAL A/C-HEATER SYSTEMS ML 320, ML 430 & ML 55
Fig. 8: Removing Instrument Panel Upper Section & Instrument Panel Carrier
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.
INTAKE AIR DUST FILTER
Removal & Installation
Remove passenger-side instrument panel lower trim panel. Release retaining clip and remove dust filter cover.
Pull dust filter down and out. See Fig. 9 . To install, reverse removal procedure.
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© 2006 Mitchell Repair Information Company, LLC.
2001 Mercedes-Benz ML320
2000-01 MANUAL A/C-HEATER SYSTEMS ML 320, ML 430 & ML 55
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Page 24
© 2006 Mitchell Repair Information Company, LLC.
2001 Mercedes-Benz ML320
2000-01 MANUAL A/C-HEATER SYSTEMS ML 320, ML 430 & ML 55
Fig. 9: Replacing Intake Air Dust Filter
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.
RECEIVER-DRIER
Removal & Installation
1. Discharge A/C system, using approved refrigerant recovery/recycling equipment. Remove headlight
units. Remove headlight units. Remove upper frame crossmember, release hood release control cable and
remove crossmember. See Fig. 6 .
2. Remove bolts from receiver-drier refrigerant lines. See Fig. 5 . Disconnect refrigerant lines from receiverdrier. Plug exposed openings to protect A/C system from debris and moisture. Discard "O" rings. Loosen
receiver-drier clamp bolt. Remove receiver-drier. To install, reverse removal procedure.
3. When installing a new receiver-drier, add 0.34 ounce of NEW refrigerant oil to receiver-drier. Use NEW
"O" rings. Tighten refrigerant line bolts to specification. See TORQUE SPECIFICATIONS .
TORQUE SPECIFICATIONS
TORQUE SPECIFICATIONS
Application
Compressor Mounting Bolts
Refrigerant Line-To-Compressor Bolt
Refrigerant Line-To-Condenser Bolt
Steering Column Bolt
Steering Column Nut
Ft. Lbs. (N.m)
15 (20)
15 (20)
15 (20)
15 (20)
13 (18)
INCH Lbs. (N.m)
89 (10)
89 (10)
Expansion Valve Self-Locking Nut
Refrigerant Line-To-Receiver-Drier Bolt
WIRING DIAGRAMS
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© 2006 Mitchell Repair Information Company, LLC.
2001 Mercedes-Benz ML320
2000-01 MANUAL A/C-HEATER SYSTEMS ML 320, ML 430 & ML 55
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Page 26
© 2006 Mitchell Repair Information Company, LLC.
2001 Mercedes-Benz ML320
2000-01 MANUAL A/C-HEATER SYSTEMS ML 320, ML 430 & ML 55
Fig. 10: Manual A/C-Heater Systems Wiring Diagram (2000-01 ML 320 Without Cooling Fan Control
Module - 1 Of 2)
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© 2006 Mitchell Repair Information Company, LLC.
2001 Mercedes-Benz ML320
2000-01 MANUAL A/C-HEATER SYSTEMS ML 320, ML 430 & ML 55
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Page 28
© 2006 Mitchell Repair Information Company, LLC.
2001 Mercedes-Benz ML320
2000-01 MANUAL A/C-HEATER SYSTEMS ML 320, ML 430 & ML 55
Fig. 11: Manual A/C-Heater Systems Wiring Diagram (2000-01 ML 320 Without Cooling Fan Control
Module - 2 Of 2)
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© 2006 Mitchell Repair Information Company, LLC.
2001 Mercedes-Benz ML320
2000-01 MANUAL A/C-HEATER SYSTEMS ML 320, ML 430 & ML 55
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Page 30
© 2006 Mitchell Repair Information Company, LLC.
2001 Mercedes-Benz ML320
2000-01 MANUAL A/C-HEATER SYSTEMS ML 320, ML 430 & ML 55
Fig. 12: Automatic A/C-Heater Systems Wiring Diagram (2000-01 ML 320 & ML 430 With Cooling Fan
Control Module - 1 Of 2)
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Page 31
© 2006 Mitchell Repair Information Company, LLC.
2001 Mercedes-Benz ML320
2000-01 MANUAL A/C-HEATER SYSTEMS ML 320, ML 430 & ML 55
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Page 32
© 2006 Mitchell Repair Information Company, LLC.
2001 Mercedes-Benz ML320
2000-01 MANUAL A/C-HEATER SYSTEMS ML 320, ML 430 & ML 55
Fig. 13: Automatic A/C-Heater Systems Wiring Diagram (2000-01 ML 320 & ML 430 With Cooling Fan
Control Module - 2 Of 2)
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Page 33
© 2006 Mitchell Repair Information Company, LLC.
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