1997 MERCEDES-BENZ ML430 cooling

OUTSIDE TEMPERATURE SENSOR RESISTANCE
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
REMOVAL & INSTALLATION
Sensor Temperature - °F (°C)Ohms
68 (20)2100
77 (25)1700
104 (40)900
122 (50)600
Step (1) Test ConditionValueSystem/Component
01.....11-14 VoltsVoltage Supply Wiring (Circuit
No. 30) & Battery
02Engine Operating At
Normal TemperatureAbout 176°F (80°C)Wiring, ECT Sensor & AAM
03Ignition ONAmbient Air Temperature
About 68°F (20°C)Wiring, Outside Temperature
Sensor & AAM
04Ignition ON, Blower At
Stage 4ON/OFFWiring, Blower Motor Relay,
Blower Motor & AAM
05Ignition ONON/OFFWiring, Engine Cooling Fan
Stage 1, Aux. Fan & AAM
08Ignition ONON/OFFWiring, Coolant Circulation Pump
Relay, Coolant Circulation Pump
& AAM
09Engine On, A/C Indicator
On, Blower Motor At
Stage 4Refrigerant Pressure At
174 psi (12 bar)(2) Refrigerant Pressure Sensor
10Engine On, A/C Indicator
On, Blower Motor At
Stage 4ON/OFF(3) AAM, A/C Compressor
11Ignition ON, Activate
A/C SystemYES/NOWiring, A/C Push Button Control
Module, AAM
(1)Step numbers not shown are not used.
(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.

2001 Mercedes-Benz ML320
2000-01 MANUAL A/C-HEATER SYSTEMS ML 320, ML 430 & ML 55
me
Saturday, October 02, 2010 3:25:10 PMPage 14 © 2006 Mitchell Repair Information Company, LLC.

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
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. NOTE: Each time A/C compressor is removed and installed, receiver-drier must be
replaced.

2001 Mercedes-Benz ML320
2000-01 MANUAL A/C-HEATER SYSTEMS ML 320, ML 430 & ML 55
me
Saturday, October 02, 2010 3:25:10 PMPage 17 © 2006 Mitchell Repair Information Company, LLC.

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 self-
locking 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
parkin
g brake release cable from handle. With assistance, remove instrument panel bottom section.

2001 Mercedes-Benz ML320
2000-01 MANUAL A/C-HEATER SYSTEMS ML 320, ML 430 & ML 55
me
Saturday, October 02, 2010 3:25:10 PMPage 21 © 2006 Mitchell Repair Information Company, LLC.

Fig. 10: Manual A/C-Heater Systems Wiring Diagram (2000-01 ML 320 Without Cooling Fan Control
Module - 1 Of 2)

2001 Mercedes-Benz ML320
2000-01 MANUAL A/C-HEATER SYSTEMS ML 320, ML 430 & ML 55
me
Saturday, October 02, 2010 3:25:10 PMPage 27 © 2006 Mitchell Repair Information Company, LLC.

Fig. 11: Manual A/C-Heater Systems Wiring Diagram (2000-01 ML 320 Without Cooling Fan Control
Module - 2 Of 2)

2001 Mercedes-Benz ML320
2000-01 MANUAL A/C-HEATER SYSTEMS ML 320, ML 430 & ML 55
me
Saturday, October 02, 2010 3:25:10 PMPage 29 © 2006 Mitchell Repair Information Company, LLC.

Fig. 12: Automatic A/C-Heater Systems Wiring Diagram (2000-01 ML 320 & ML 430 With Cooling Fan
Control Module - 1 Of 2)

2001 Mercedes-Benz ML320
2000-01 MANUAL A/C-HEATER SYSTEMS ML 320, ML 430 & ML 55
me
Saturday, October 02, 2010 3:25:10 PMPage 31 © 2006 Mitchell Repair Information Company, LLC.

Fig. 13: Automatic A/C-Heater Systems Wiring Diagram (2000-01 ML 320 & ML 430 With Cooling Fan
Control Module - 2 Of 2)

2001 Mercedes-Benz ML320
2000-01 MANUAL A/C-HEATER SYSTEMS ML 320, ML 430 & ML 55
me
Saturday, October 02, 2010 3:25:10 PMPage 33 © 2006 Mitchell Repair Information Company, LLC.

Fig. 2: Identifying Ventilation Function - Air Distribution Duct
Function
The ventilation system ensures:
that the windshield and windows are kept without mist.
that there is a supply of fresh air to the vehicle occupants.
that constant and pleasant temperatures are quickly achieved in the vehicle interior.
Ventilation is achieved with the assistance of the blower motor during normal operation, when vehicle is
stationary or to increase the air quantity.
Fresh air is drawn into the evaporator housing via the air inlet. Depending on the automatic air conditioning
push-button control module setting, the air is directed through the air ducts to the air vents in the interior.
The air flows out of the vehicle again through the rear vent via ventilation slots to the left and right in the area
below the rear side windows.
In recirculation mode, air is drawn out from the vehicle interior via the fresh air/recirculation flap (recirculation
setting) by the blower motor and passed to the evaporator housing.
The ventilation is essentially divided into heating operation and cooling operation.
Heating operation

2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
Saturday, October 02, 2010 3:23:14 PMPage 7 © 2006 Mitchell Repair Information Company, LLC.