1997 MERCEDES-BENZ ML320 engine

AR88.40-P-3000GH
Remove/install engine hood
25.3.97

MODEL
163.113 /128 /136 /154 /157 /172 /174 /175

P88.40-2062-01

1
Screws

2
Gas pressure strut


Removing and installing


Danger!

Risk of injury
to
fingers being jammed or

squeezed
when removing and installing or

aligning hoods, doors, trunk lid/tailgate or

sliding roof.
When moving components, ensure that no

body parts or limbs are within the operating

range of moving parts.

AS00.00-Z-0011-01A

1
Open engine hood and raise to vertical position

Up to VIN A145272, X708318.

AR88.40-P-1000GH

As of VIN A145273, X708319.

AR88.40-P-1000GI

2
Mark position of engine hood hinges on

engine hood

Facilitates installation.

3.1
Remove gas strut (2)


Secure engine hood with helper to avoid

damage.

AR88.40-P-3010GH

As of VIN A145273, X708319.

4
Remove screws (1)


Installation:
Paint screws.


*BA88.40-P-1001-01C

5
Remove engine hood


Use helper to avoid damage. Set down on

suitable surface.

6
Install in the reverse order

Align engine hood on engine hood hinges

at markings made previously.

7
Check alignment of engine hood

If necessary:
#

Adjust engine hood

AR88.40-P-3020GH


Engine hood

Number

Designation
Model 163

BA88.40-P-1001-01C
Screw for engine hood hinge on engine hood
Nm
10

Copyright DaimlerChrysler AG 09.05.2006 CD-Ausgabe G/10/04 . This WIS print-out will not be recorde
d by Modification services.
Page 1

AR88.40-P-3010GH
Remove/install gas-operated strut on engine hood
6.4.99

MODEL
163.136 /154 /172 #A as of 145273,

163.136 /154 /172 #X as of 708319,

163.113 /128 /157 /174 /175

P88.40-2063-06

1
Gas pressure strut

2
Fuse


Remove, Install

1
Open engine hood

2
Secure engine hood

3
Lift retainer (2) on top of gas-operated strut

(1) and detach gas-operated strut at the top


Risk of breakage. Do not remove the

retainer otherwise the preload will be lost.

4
Lift retainer on bottom of gas-operated strut

and remove gas-operated strut (1)

When replacing gas pressure strut:
#

Danger!

Risk of injury
due to drilling gas-filled

equipment or components (gas filling not

flammable)
Wear safety goggles and face mask.

AS00.00-Z-0006-01A

o

Degas and drain gas pressure strut

OS00.00-P-1001-01A

5
Install in the reverse order

Copyright DaimlerChrysler AG 09.05.2006 CD-Ausgabe G/10/04 . This WIS print-out will not be recorde
d by Modification services.
Page 1

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
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 NOTE: Function test steps must be performed in order given.

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 9 © 2006 Mitchell Repair Information Company, LLC.

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 (15-
amp).
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.

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 10 © 2006 Mitchell Repair Information Company, LLC.

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 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. 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.

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 15 © 2006 Mitchell Repair Information Company, LLC.

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.

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 22 © 2006 Mitchell Repair Information Company, LLC.

BLOWER MOTOR FUNCTION - GF83.10-P-2170-01GI
Function
The AAC push-button control module (N22) passes a control voltage of 0-6 V to the blower regulator (A32n1)
via the AC bus. Depending on the control voltage which is present, this then regulates the blower motor
(A32m1) operating voltage of 0-12 V. This facilitates blower speed control of 0-100 %.
The blower motor actuation (operating voltage) is influenced by the following factors:
Blower power setting manual or AUTO
Operating functions:
Air distribution
AC OFF mode
Residual engine heat mode (actuation limited to 5 V)
Mode status (heating, cooling)
Coolant temperature
Vehicle speed
Fresh air/recirculation flap setting
Flap positions
Terminal 15 (blower ON), starter running (blower OFF)
BLOWER MOTOR LOCATION/TASK/DESIGN/FUNCTION - GF83.10-P-2170GI
MODEL 163 as of 1.9.01 with CODE (580a) Automatic air conditioning
Blower, task
The rear blower motor (M2/1) serves to improve ventilation and cooling
in the rear.
The air that is drawn in by the blower in the evaporator housing is led to
the rear blower motor (M2/1) via air ducts.
The rear blower motor (M2/1) increases the flow of air.

Blower,
function GF83.10-P-
2168-01GI

2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
Saturday, October 02, 2010 3:23:15 PMPage 33 © 2006 Mitchell Repair Information Company, LLC.