1997 MERCEDES-BENZ ML500 recirculation

Fig. 65: Identifying Fresh Air/Recirc ulated Air Flap Actuator Motor
FRESH AIR/RECIRCULATED AIR FLAP ACTUATOR MOTO R, FUNCTION - GF83.30-P-2105-02GH
Function
The fresh air/recirculated air flap actuator motor (M39) is controlled via the recirculation air switch ( ) and
when the temperature selector switch is set to max. cooling output in the control module (S98).
Recirculated air mode (100 % recirculated air)
In the recirculated air mode the supply of fresh air is closed by the fresh air/recirculated air flap actuator motor
(M39) and simultaneously the recirculated air supply opened without any time limit.
Fresh air mode (100 % fresh air)
In the fresh air mode the supply of fresh air is opened by th e fresh air/ recirculated air flap actuator motor (M39)
and simultaneously the recirculated air supply closed without any time limit.
Auxiliary function at air conditioning (TAC)
When, in the cooling mode, the temperat ure selector wheel is set to max. cooling (position indented blue) then
at the same time the fres h air/recirculated air flap actuator moto r (M39) is controlled and switched to
recirculation air wi thout time limit.
FRESH AIR/RECIRCUL ATED AIR FLAP ACTUATOR, FU NCTION - GF83.30-P-2105-02GI
Function
Pressing the recirculating air push- button ( ) on the AAC push-button control module (N22) actuates the
fresh air/recirculated air flap actuator motor (M2/5) via the air conditioner bus.
In recirculation mode, the recircul ation air supply is closed off by th e fresh air/recirculated air flap.
In fresh air mode, the fresh air supply is ope ned by the fresh air/ recirculated air flap.

2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
Saturday, October 02, 2010 3:23:15 PMPage 74 © 2006 Mitchell Repair Information Company, LLC.

Control of fresh air/recirculated air flap via the AAC push-button control module (N22)
When the recirculating air push-button is pressed ( ) on the AAC push-button control module the system is
switched by means of the fresh air/recirculated air flap actuator motor straight to 100 % recirculation air. This is
displayed by the function LED.
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.
AIR CONDITIONING FLUID RESERVOIR, LOCATION - GF83.30-P-2106-01GH
The fluid reservoir (6) is located in the left front of the engine compartment, next to the condenser.
Fig. 66: Identifying Air Conditioning Fluid Reservoir And Associated Components

AIR CONDITIONING FLUID RESERVOIR, FUNCTION - GF83.30-P-2106-02GC
Function
NOTE: The recirculated air function can be terminated after a set time-out in
accordance with country specifications.
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 75 © 2006 Mitchell Repair Information Company, LLC.

Lateral nozzle, location/purpose/function GF83.10-P-
2150GC
Front footwell air outlet, location/purpose/ function GF83.10-P-
2145GC
Rear footwell air outlet, location/purpose/ function GF83.10-P-
2146GC
Heating system heat exchanger, location/
purpose/function GF83.20-P-
2108GC
Fresh air/recirculation flap, location/purpose/ function GF83.20-P-
2111GC
Fresh air/recirculation flap actuator, location/
purpose/function GF83.30-P-
2116GC
Blower switch, location/purpose/design/function GF83.25-P-
2100GC
Air distribution switch, location/purpose/design/
function GF83.25-P-
2101GH
Temperature selector wheel, location/purpose/
design/function GF83.25-P-
2102GC
Air recirculation switch, location/purpose/
design/function GF83.10-P-
2117GH
AC button, location/purpose/function GF83.30-P-
2103GH
AC control module, location/purpose/function GF83.30-P-
2102GH
All-activity module, location/purpose/function GF54.21-P-
4110GH
A/C housing, location/purpose/function GF83.30-P-
2119GH
Auxiliary fan, location/purpose/functionENGINE 111.977, 112.942GF83.40-P-
2162GH
Electric fan motor/air conditioning system,
location/purpose/functionEngine 113.942, 113.981 and
612.963, 628.963GF83.40-P-
2151GH
Condenser, location/purpose/function GF83.40-P-
2152GC
Evaporator location/purpose/design/function GF83.40-P-
2121GC
Fluid reservoir (TAC), location/purpose/function GF83.30-P-
2120GC
Expansion valve, location/purpose/design/ function GF83.40-P-
2123GC
Refrigerant pressure sensor, location/purpose/ function GF83.40-P-
2156GH
Refrigerant compressor, location/purpose/
design/function GF83.55-P-
2100GH

2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
Saturday, October 02, 2010 3:23:15 PMPage 79 © 2006 Mitchell Repair Information Company, LLC.

Air distribution button ( ) = air duc ting to rear compartment nozzle
Air distribution button ( ) = air ducting to the air outlets in the rear footwell
The automatic air distribution function can be set by pr essing the Auto button, whereby control is assumed by
the AAC push-button c ontrol module (N22).
RECIRCULATING AIR PU SH-BUTTON, FUNCTION - GF83.40-P-2102-01GI
Function
A brief actuation (< 1.5 s) of the recirculating air pus h-button ( ) energizes the actuator motor for the fresh
air/recirculated air flap, whic h activates the fresh air/recirculated air fl ap and thus closes the fresh air duct and
opens the recirculation duct, in or der to enable the air supply from the passenger compartment. The function
LED illuminates during recirculation mode.
Recirculated air convenience closing function
If the recirculating air pus h-button ( ) is pressed for longer than > 2 s, then alongside the recirculation
function, all open windows and the sliding and tilting roof are automatically closed (window and sliding/
tilting roof must ha ve been normalized ). The function LED illuminates durin g recirculation mode. In order to
prevent any current peaks the sliding/tilting sunroof and power windows are actuated successively.
If the push-button is pressed again for > 2 s, the windows a nd the sliding/tilting sunroof return to the previously
stored position and the fresh air/ recirculated air flap moves to the fresh air position (LED off).
The convenience closing function can only be started if the recirculating LED is not illuminated.
Each window, which has been manually opened during the r ecirculation phase, remains in this position if the
recirculating function is cleared: all other windows move to the stor ed positions. The position of the
sliding/tilting sunroof prior to the st art of the closing operation and that of the side windows is stored in the
memory. The windows and the sliding/tilting sunroof wh ich have been closed by the convenience closing
function, remain closed if the recirculation push-
button was only pressed briefly (t < 1.5 s). In this case, only the
fresh air/recirculated air flap is moved to the fresh-air position. The stored positions are cleared when the
ignition is switched off.
AUTOMATIC AIR CONDITIONING BOX FUNCTION - GF83.40-P-2105-02GI
Operating condition: Air ducting under heater operation

2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
Saturday, October 02, 2010 3:23:16 PMPage 90 © 2006 Mitchell Repair Information Company, LLC.

Fig. 75: Identifying Automatic Air Conditioning Box Function - Operating Condition Air Ducting In
Blending Mode (Hot/Cold) Closed-Loop Operation
Operating condition: Blend air (warm/cold) Function
When in blending mode, the blower motor (5) draws in fresh air (A) to the automatic air conditioning box and
routes it through the multipurpose filter (3). The air cleaned by the multipurpose filter (3) is then routed to the
evaporator core (2) and dried there. Some of the dried, cooled and filtered air (B) is routed onwards by the heat
exchanger (1) and some is routed around the heat exchanger (1). This air conduction is controlled via the center
setting of the blending air flaps (6).
The dried, cooled and filtered air (B) which was routed through the heat exchanger (1) is then heated up again.
After passing through the blending air flaps (6) this heated air (C) is mixed up to form blend air (D) with the
dried, cooled and filtered air, which was routed around the heat exchanger (1). This blend air (D) is then routed
via the air outlets (E, F, FR, M and S) into the passenger compartment. The fresh air/recirculated air flap (4) is
closed.
Operating condition: Air ducting "recirculation air" in cooling mode

2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
Saturday, October 02, 2010 3:23:16 PMPage 93 © 2006 Mitchell Repair Information Company, LLC.

Fig. 76: Identifying Automatic Air Conditioning Box Function - Operating Condition Air Ducting
Recirculation Air In Cooling Mode
Operating condition: Cooling down "recirculation air" Function
In cooling mode with recirculated air, the blower motor (5) draws in recirculated air (A) from the passenger
compartment via the opened fresh air/recirculated air flap (4) into the automatic air-conditioning box and routes
it through the multipurpose filter (3). The air cleaned by the multipurpose filter (3) is then routed to the
evaporator core (2) and dried there. The dried, cooled and filtered air (B) is then routed around the heat
exchanger (1). This air conduction is controlled via the setting of the blend air flap (6).
The dried, cooled and filtered air (B) is routed directly into the passenger compartment via the air outlets (E, F,
FR, M and S). The supply of fresh-air is cut off by the fresh air/recirculation flap (4).
AUTOMATIC AIR CONDITIONING BOX, DESIGN - GF83.40-P-2105-04GI
The automatic air conditioning box consists of the following components
Air ducting flaps
Combination filter
Blower motor
Blower regulator
Evaporator
Heating system heat exchanger
Expansion valve

2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
Saturday, October 02, 2010 3:23:16 PMPage 94 © 2006 Mitchell Repair Information Company, LLC.

function 2146GI
Blower motor,
location/purpose/design/function GF83.10-P-
2170GI
Blower regulator, location/purpose/function GF83.10-P-
2141GI
Rear blower motor, location/purpose/design/
function GF83.10-P-
2168GI
Rear electronic blower regulator, location/
purpose/function GF83.10-P-
2176GI
Combination filter, location/purpose/function GF83.10-P-
2128GI
Defroster vent flap actuator motor, location/
purpose/function GF83.10-P-
2175GI
Footwell flap actuator,
location/purpose/function GF83.10-P-
2132GI
Actuator motor, center nozzle flap, location/
purpose/function GF83.10-P-
2172GI
Actuator motor, rear shut-off flap, location/
purpose/function GF83.10-P-
2171GI
Actuator motor, rear air distribution flap,
location/purpose/function GF83.10-P-
2173GI
Heating system heat exchanger, location/
purpose/function GF83.20-P-
2108GC
Heating water circulation pump, location/
purpose/function GF83.20-P-
2109GI
Fresh air/recirculation flap, location/purpose/
function GF83.20-P-
2111GC
Fresh air/recirculation flap actuator, location/
purpose/function GF83.30-P-
2116GC
Blower switch,
location/purpose/design/function GF83.25-P-
2100GI
Blower button, location/purpose/functionRear ventilation operating moduleGF83.40-P-
2144GI
Air distribution switch,
location/purpose/design/ function GF83.25-P-
2101GI
Air distribution button,
location/purpose/functionRear ventilation operating moduleGF83.40-P-
2159GI
Temperature selector wheel, location/purpose/
design/function GF83.25-P-
2102GI
Defroster button, location/purpose/function GF83.40-P-
2139GI
Recirculating air push-button,
location/purpose/ function GF83.40-P-
2145GI
GF83.40-P-

2001 Mercedes-Benz ML320
1998-2005 HVAC Climate Control - 163 Chassis
me
Saturday, October 02, 2010 3:23:16 PMPage 118 © 2006 Mitchell Repair Information Company, LLC.