1997 MERCEDES-BENZ ML350 air conditioning

Function
Rotating the air distribution switch in the AAC push-
button control module (N22) actuates the center outlet flap
actuator motor (M2/22) via the AC bus. The center outlet flap actuator motor (M2/22) controls the center outlet
flap, which adopts the following positions according to requirements.
Switching logic
center outlet flap closed = 0%
center outlet flap open = 100%
Automatic center outlet flap control (Auto button engaged)
The center outlet flap is opened depending on the following values
blending air flap setting
Coolant temperature
Evaporator temperature
linear up to 100 % open.
Center outlet flap control via push-button control module (Clock type switch setting of air distribution
switch)
If a problem exists, it is possible to retrieve and verify the defined end positions by means of the diagnosis
assistant system (DAS) (valuation trip).
After replacing an actuator motor an adjustment run must be performed using the Diagnosis Assistant System
(DAS), i.e. the flap OPEN and SHUT limit positions are defined and retained.
CENTER OUTLET FLAP ACTUATOR MOTOR, LOCATION/TASK/FUNCTION - GF83.10-P-2172GI
MODEL 163 as of 1.9.01 with CODE (580a) Automatic air conditioning
1 o'clock 2 o'clock 3 o'clock 4 o'clock 5 o'clock6 o'clock
65% 82% 100% 68% 2%
0%
7 o'clock 8 o'clock 9 o'clock 10 o'clock 11 o'clock
12 o'clock
32% 68% 100% 82% 65%
50%
NOTE: All actuator motors are identical.

2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
Saturday, October 02, 2010 3:23:15 PMPage 36 © 2006 Mitchell Repair Information Company, LLC.

(DAS), i.e. the end positions flap OPEN and SHUT are defined and retained.
REAR AIR DISTRIBUTION FLAP ACTUATOR MOTOR, LOCATION/TASK/FUNCTION - GF83.10-P-2173GI
MODEL 163 as of 1.9.01 with CODE (580a) Automatic air conditioning
Fig. 30: Locating Rear Air Distribution Flap Actuator Motor

DEFROSTER VENT FLAP ACTUATOR MOTOR, FUNCTION - GF83.10-P-2175-01GI
Function
Pressing the defroster button ( ) on the AAC push-button control module actuates the defroster vent flap
actuator motor (M2/8) via the air conditioner bus. The defroster vent flap actuator motor (M2/8) controls the
defroster nozzle flaps, which adopt the followin
g positions, according to requirements:

Rear air distribution
flap actuator motor
locationThe rear air distribution flap actuator motor (M2/21) is to the left
of the rear blower housing, behind the rear compartment nozzle.

Rear air distribution
flap actuator motor
taskThe rear air distribution flap actuator motor (M2/21) operates the
rear air distribution flap for controlling the flow of air to the rear
compartment nozzle and the rear footwell air vents.


Rear air distribution
flap actuator motor
function
GF83.10-P-
2173-01GI

2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
Saturday, October 02, 2010 3:23:15 PMPage 38 © 2006 Mitchell Repair Information Company, LLC.

Defrost function
Defroster nozzle flap open 100 %.
System switched off
Defroster nozzle flap open 100 % (This limp-home capability ensures that the windshield will not fog up even
when a malfunction has occurred)
Defroster nozzle flap control via the push-button control module
(Clock type switch setting of air distribution switch)
If a problem exists, it is possible to retrieve and verify the defined end positions by means of the diagnosis
assistant system (DAS) (valuation trip).
After replacement of an actuator motor it is necessary for an adjustment run to be performed using the diagnosis
assistant system (DAS), i.e. the end positions flap OPEN and SHUT are defined and retained.
DEFROSTER VENT FLAP ACTUATOR MOTOR, LOCATION/TASK/FUNCTION - GF83.10-P-2175GI
Model 163 as of 1.9.01 with code (580a) Automatic air conditioning
1 o'clock 2 o'clock 3 o'clock 4 o'clock 5 o'clock6 o'clock
85% 68% 50% 32% 17%
0%
7 o'clock 8 o'clock 9 o'clock 10 o'clock 11 o'clock
12 o'clock
0 % 0 % 0 % 32 % 70 %
100 %
NOTE: All actuators are identical.

2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
Saturday, October 02, 2010 3:23:15 PMPage 39 © 2006 Mitchell Repair Information Company, LLC.

REAR ELECTRONIC BLOWER REGULATOR, LOCATION/TASK/FUNCTION - GF83.10-P-2176GI
Model 163 as of 1.9.01 with code (580a) Automatic air conditioning
Fig. 32: Identifying Rear Electronic Blower Regulator

HEATER FUNCTION - GF83.20-P-0002GH
MODEL 163 up to 31.8.01
Function
The heater enables a pleasant interior climate for the vehicle passengers in the event of different weather
conditions.
A nominal temperature is preset at the heater push-button control module temperature selector wheel. This
setting is transmitted to the blending air flaps in the heater housing via a cable and an actuation mechanism.
Rear electronic blower
regulator, locationThe rear electronic blower regulator (N29/2) is located behind
the rear nozzle below the center console.
Rear electronic blower
regulator, taskThe rear electronic blower regulator (N29/2) controls the rear
blower motor (M2/1) voltage supply depending on the relevant
blower level setting.

Rear electronic blower
regulator, function GF83.10-P-
2176-01GI

2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
Saturday, October 02, 2010 3:23:15 PMPage 41 © 2006 Mitchell Repair Information Company, LLC.

Control is then carried out there as follows:
Temperature selector wheel MAX setting (full heater output)
Due to the setting of the blending air flaps, the drawn in air is routed through the heat exchanger. Heated
cooling water generally flows through this, as a result of which the passing air is heated. The temperature-
controlled air is guided into the vehicle interior via the various air outlets.
Temperature selector wheel MIN setting (no heater output)
In this setting, the blending air flaps block the route to the heat exchanger. The drawn in fresh air is guided
directly to the air outlets and therefore into the vehicle interior.
HEATER FUNCTIONAL DESCRIPTION TABLE OF CONTENTS - GF83.20-P-0998GH
MODEL 163 up to 31.8.01 except CODE (580) Air conditioning or Tempmatic for USA
Ventilation system function GF83.10-P-2000GH
Heater circuit function GF83.20-P-2003GH
Heater controls, function GF83.20-P-2004GH
Heater function GF83.20-P-0002GH
Ventilation system function GF83.10-P-2000GH
Heater circuit function GF83.20-P-2003GH
Heater controls, function GF83.20-P-2004GH
Air inlet, location/function GF83.10-P-2138GC
Air ducts, location/task/design GF83.10-P-2139GH
Blower, location/task/design/function GF83.10-P-2102GC
Series resistor group, location/task/function GF83.10-P-2161GC
Dust filter, location/task/function GF83.10-P-2142GH
Rear vent, location/task/function GF83.10-P-2143GC
Defroster vent, location/task/function GF83.10-P-2144GC
Center nozzle, location/task/function GF83.10-P-2149GC
Lateral nozzle, location/task/function GF83.10-P-2150GC
Front footwell air outlet, location/task/function GF83.10-P-2145GC
Rear footwell air outlet, location/task/function GF83.10-P-2146GC
Heating system heat exchanger, location/ purpose/function GF83.20-P-2108GC
Fresh air/recirculated air flap, location/task/ function GF83.20-P-2111GC
Fresh air/recirculated air flap actuator, location/ task/function GF83.30-P-2116GC
Blower switch, location/task/design/function GF83.25-P-2100GC
Air distribution switch, location/task/design/ function GF83.25-P-2101GH
Temperature selector wheel, location/task/ design/function GF83.25-P-2102GC
Air recirculation switch, location/task/design/ function GF83.10-P-2117GH

2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
Saturday, October 02, 2010 3:23:15 PMPage 42 © 2006 Mitchell Repair Information Company, LLC.

The fresh air/recirculated air flap shuts off the supply of recirculated air.
Fresh air is drawn in.
Recirculation mode
The fresh air/recirculated air flap shuts off the supply of fresh air. Air is drawn in from the passenger
compartment.
HEATER CORE, LOCATION/PURPOSE/FUNCTION - GF83.20-P-2108GC
MODEL 163, 168
HEATING WATER CIRCULATION PUMP, LOCATION/TASK/FUNCTION - GF83.20-P-2109GI
MODEL 163 as of 1.9.01 with code (580a) Automatic air conditioning
Fig. 41: Identifying Heating Water Circulation Pump

Heater core,
locationModel 168GF83.20-P-
2101-02GC
Model 163GF83.20-P-
2101-02GH
Heater core,
purposeThe heater core serves for heating up the air flowing through on the way
to the various defroster, ventilation and heating nozzles in the vehicle
passenger compartment.

Heater core,
function GF83.20-P-
2101-01GC

Heating water
circulation pump,
positionThe heating water circulation pump (M13) is located at the front
right in the engine compartment next to the coolant compensating
reservoir.


Heating water
circulation pump
taskThe heating water circulation pump (M13) serves to maintain a
constant flow of hot water through the heat exchanger in the event of
low engine speeds and residual engine heat utilization.


2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
Saturday, October 02, 2010 3:23:15 PMPage 51 © 2006 Mitchell Repair Information Company, LLC.

HEATER HOUSING POSITION/TASK/FUNCTION - GF83.20-P-2110GC
MODEL 163 up to 31.8.01
168 up to except CODE (580) Air conditioning or Tempmatic for USA
Shown on model 168 as of 1.03.01
Fig. 42: Identifying Heater Housing
- Shown On Model 168 As Of 1.03.01
FRESH AIR/RECIRCULATED AIR FLAP, LOCATION/PURPOSE/FUNCTION - GF83.20-P-2111GC
MODEL 163, 168

Heating water
circulation pump
function
GF83.20-P-
2102-01GI
Heater housing
positionThe heater housing (1) is located beneath the instrument
panel.
Model 168 up to 28.02.01GF83.20-P-2103-
01GC
Model 163GF83.20-P-2103-
01GH
Heater housing task GF83.20-P-2103-
03GC
Heater housing
functionModel 168GF83.20-P-2103-
02GC
Model 163GF83.20-P-2103-
02GH

2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
Saturday, October 02, 2010 3:23:15 PMPage 52 © 2006 Mitchell Repair Information Company, LLC.

blower level 2 --> blower level 3
may lead to an increase in the speed of the blower motor due to the short-term bridging of two contact plates
(intermediate setting).
BLOWER SWITCH, LOCATION/TASK/DESIGN/FUNCTION - GF83.25-P-2100GC
MODEL 163 up to 31.8.01 168
Shown on model 168 with heating as of 01.03.01
Fig. 44: Identifying Blower Switch (Model 168 With Heating As Of 01.03.01)

BLOWER SWITCH, LOCATION/TASK/DESIGN/FUNCTION - GF83.25-P-2100GI
MODEL 163 as of 1.9.01 with code (580a) Automatic air conditioning
Blower switch,
locationThe blower switch (N119s3) is located on the left in the heater
push-button control module.
Model 168 up to 28.02.01GF83.25-P-2100-
01GC
Model 163GF83.25-P-2100-
01GH
Blower switch,
taskThe blower switch activates several blower stages in fresh air
and recirculating air mode.
Blower switch
designThe blower switch is designed as a multi-level rotary switch with
an axis and wiper contact.
Blower switch,
function GF83.25-P-2100-
02GC

2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
Saturday, October 02, 2010 3:23:15 PMPage 54 © 2006 Mitchell Repair Information Company, LLC.