Mercedes-Benz ML320. Service manual - part 663

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'clock

6 o'clock

85%

68%

50%

32%

17%

7 o'clock

8 o'clock

9 o'clock

10 o'clock

11 o'clock

12 o'clock

0 %

32 %

70 %

100 %

NOTE:

All actuators are identical.

2001 Mercedes-Benz ML320

1998-2005 HVAC Climate Control - 163 Chassis

Fig. 31: Identifying Defroster Vent Flap Actuator Motor

ELECTRONIC BLOWER CONTROL UNIT, REAR VENTILATION, FUNCTION - GF83.10-P-2176-01GI

Function

The blower push-button (

) in the rear ventilation control panel (N72/2s3) is used to send a control voltage

to the rear electronic blower regulator (N29/2). Depending on the control voltage (0 - 6 V) present, this then
regulates the operating voltage (0 -12 V) for the rear blower motor (M2/1). This facilitates blower speed control
of 0-100%.

Automatic operation, function

By pressing the Auto button (

) in the rear ventilation control panel the control of the rear electronic blower

regulator and thus that of the rear blower motor is governed by the AAC push-button control module.

Defroster vent flap
actuator motor,
location

The defroster vent flap actuator motor (M2/8) is located at the left
side of the air conditioner housing.

Defroster vent flap
actuator motor, task

The defroster vent flap actuator motor (M2/8) operates the
defroster vent flaps for air flow control to the windshield defroster
vent and side window defroster vents.

Defroster vent flap
actuator motor,
function

GF83.10-P-
2175-01GI

2001 Mercedes-Benz ML320

1998-2005 HVAC Climate Control - 163 Chassis

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, location

The rear electronic blower regulator (N29/2) is located behind
the rear nozzle below the center console.

Rear electronic blower
regulator, task

The 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

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

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