2007 MERCEDES-BENZ GL450 Ac compressor

223 Controls in detail
Climate control
Adjusting air distribution
Move air vent slider2 to the left, right,
up, or down to direct the air in the de-
sired direction.
Front defroster
You can use this setting to defrost the
windshield, for example if it is iced up. You
can also use it to defog the windshield and
door windows.
Activating
Press button0 or, depending on
vehicle production date, button|
(
page 218).
The indicator lamp on the button
comes on.The climate control switches to the follow-
ing functions automatically:

most efficient blower speed and
heating power, depending on outside
temperature

air flows onto the windshield and the
door windows (side air vents must be
open)

the air conditioning compressor
switches on at outside temperatures
above approximately 41°F (5°C) for
air-drying
Adjustments
You can adjust the air volume and the tem-
perature when the front defroster is
switched on. The air flow will remain on the
windshield and door windows.
Press button
to decrease or
buttonQ to increase air volume
(
page 218) to the desired level.The air volume decreases/increases to
the next lower/higher blower speed
and heating switches to the tempera-
ture that was set before the front de-
froster was switched on.
The indicator lamp on button0 or,
depending on vehicle production date,
button| goes out. The indicator
lamp on button9 comes on.
or
Turn temperature control1
and/or7 (
page 218) slightly in any
direction.
Heating switches to the temperature
that was set before the front defroster
was switched on.
The indicator lamp on button0 or,
depending on vehicle production date,
button| goes out. The indicator
lamp on button9 comes on.iKeep this setting selected only until the
windshield or the door windows are clear again.


224 Controls in detail
Climate control
Deactivating
Press button0 or, depending on
vehicle production date, button|
(
page 218) once more.
The indicator lamp on the button goes
out. Defrosting is turned off.
The previous settings are in effect
again. The air conditioning compressor
remains switched on.Windshield fogged on the outside
Switch the windshield wipers on
(
page 64).
Press button0 or, depending on
vehicle production date, button|
(
page 218).
The indicator lamp on the button
comes on.
The climate control switches automatically
to the following functions:

most efficient blower speed and
heating power, depending on outside
temperature

air flows onto the windshield and the
door windows (side air vents must be
open)

the air conditioning compressor
switches on at outside temperatures
above approximately 41°F (5°C) for
air-dryingIf the automatic air distribution is switched
off:
Press air distribution button9 ora
(
page 218).
Air recirculation mode
Switch to air recirculation mode to prevent
unpleasant odors from entering the vehicle
from the outside (e.g. before driving
through a tunnel). This setting cuts off the
intake of outside air and recirculates the
air in the passenger compartment.
iThe air conditioning compressor remains on
even if the indicator lamp in button0 or, de-
pending on vehicle production date, button|
goes out. This helps to prevent the windshield
from fogging.
iTo switch off, you can also press
button´ orU (
page 218).
iKeep this setting selected only until the
windshield is clear again.
Warning!G
Fogged windows impair visibility,
endangering you and others. If the windows
begin to fog on the inside, switching off the
air recirculation mode immediately should
clear interior window fogging. If interior win-
dow fogging persists, make sure the air
conditioning (
page 218) is activated, or
press button0 or, depending on vehicle
production date, button|.


227 Controls in detail
Climate control
Deactivating
It is possible to deactivate the air condi-
tioning (cooling) function of the climate
control system. The air in the vehicle will
then no longer be cooled or dehumidified.
Press button9 (page 218).
The indicator lamp on the button goes
out.
Activating
Moist air can fog up the windows. You can
dehumidify the air with the air condition-
ing.
Press button9 (page 218) again.
The indicator lamp on the button
comes on.
The air conditioning uses the refrigerant
R134a. This refrigerant is free of CFCs
which are harmful to the ozone layer.
Residual heat and ventilation
With the engine switched off, it is possible
to continue to heat or ventilate the interior
for up to 30 minutes. This feature makes
use of the residual heat produced by the
engine.Activating
Switch off the ignition (page 42).
Press button9 (page 218).
The indicator lamp on the button
comes on.
Deactivating
Press button9 (page 218).
The indicator lamp on the button goes
out.
!If the air conditioning cannot be turned on
again, this indicates that the air conditioning is
losing refrigerant. The compressor has turned
off.
Have the air conditioning checked at the nearest
authorized Mercedes-Benz Light Truck Center.
iHow long the system will provide heating
depends on

the coolant temperature

the battery voltage
Regardless of the temperature and air volume
set on the climate control panel, the interior tem-
perature is set to 72°F (22°C) and the blower
runs on low speed to protect the vehicle battery.
iThe residual heat is automatically turned off:

when the ignition is switched on

after about 30 minutes

if the coolant temperature is too low

if the battery voltage drops

237 Controls in detail
3-zone automatic climate control*
Adjusting air volume
Five blower speeds are available.
Press button
to decrease or
buttonQ to increase air volume
(
page 232) to the desired level.
The indicator lamp on buttonU
goes out.
The automatic mode is switched off.
The selected blower speed appears in
the displaye (
page 232).
Front defroster
You can use this setting to defrost the
windshield, such as when it is iced up. You
can also use it to defog the windshield and
door windows.
Activating
Press button0 or, depending on
vehicle production date, button|
(
page 232).
The indicator lamp on the button
comes on.The automatic climate control switches to
the following functions automatically:

most efficient blower speed and
heating power, depending on outside
temperature

air flows onto the windshield and the
door windows (side air vents must be
open)

the air conditioning compressor
switches on at outside temperatures
above approximately 41°F (5°C) for
air-drying
Adjustments
You can adjust the air volume and the tem-
perature when the front defroster is
switched on. The air flow will remain on the
windshield and door windows.
iKeep this setting selected only until the
windshield or the side windows are clear again.

238 Controls in detail
3-zone automatic climate control*
Press button
to decrease or
buttonQ to increase air volume
(
page 232) to the desired level.
The air volume decreases/increases to
the next lower/higher blower speed
and heating switches to the tempera-
ture that was set before the front de-
froster was switched on.
The indicator lamp on button0 or,
depending on vehicle production date,
button| goes out. The indicator
lamp on button9 comes on.
or
Turn temperature control1
and/or7 (
page 232) slightly in any
direction.
Heating switches to the temperature
that was set before the front defroster
was switched on.
The indicator lamp on button0 or,
depending on vehicle production date,
button| goes out. The indicator
lamp on button9 comes on.Deactivating
Press button0 or, depending on
vehicle production date, button|
(
page 232).
The indicator lamp on the button goes
out. Defrosting is turned off.
The previous settings are once again in
effect.Windshield fogged on the outside
Switch the windshield wipers on
(
page 64).
Press buttonU (page 232).
The indicator lamp on buttonU
goes out. Air volume and air
distribution are controlled separately
for each zone.
If the automatic air distribution and
air volume are switched off:
Press buttons8 andY
(
page 232).
iThe air conditioning compressor remains on
even if the indicator lamp in button0 or, de-
pending on vehicle production date, button|
goes out. This helps to prevent the windshield
from fogging.
iTo switch off, you can also press
button´ orU (
page 232).
iKeep this setting selected only until the
windshield is clear again.

242 Controls in detail
3-zone automatic climate control*
Using driver-side settings for all tem-
perature zones
You can use the settings of the driver’s
side, such as temperature, air volume and
air distribution, for all temperature zones.
These settings only need to be made once
and the automatic climate control system
will automatically regulate the settings for
all temperature zones quickly and comfort-
ably.Activating
Adjust the temperature, air volume and
air distribution (
page 232).
Press button; (page 232).
The indicator lamp on the button
comes on.
The driver-side settings are used for all
temperature zones.
Deactivating
Press button; (page 232) again.
The indicator lamp on the button goes
out.
Residual heat and ventilation
With the engine switched off, it is possible
to continue to heat or ventilate the interior
for up to 30 minutes. This feature makes
use of the residual heat produced by the
engine.!If the air conditioning cannot be turned on
again, this indicates that the air conditioning is
losing refrigerant. The compressor has turned
off.
Have the air conditioning checked at the nearest
authorized Mercedes-Benz Light Truck Center.
iIf you manually set the temperature, air vol-
ume or air distribution for the passenger side or
the rear passenger compartment when the
MONO setting is active, the MONO setting will
be switched off.
iHow long the system will provide heating
depends on

the coolant temperature

the battery voltage
Regardless of the temperature and air volume
set on the automatic climate control panel, an
interior temperature is aimed at by 72°F (22°C)
and the blower runs on low speed to protect the
vehicle battery.

491 Practical hints
What to do if …
Display symbolDisplay messagesPossible cause/consequencePossible solution
Visit workshopThe air suspension is malfunctioning.Do not drive faster than 50 mph
(80 km/h) depending on the set vehi-
cle level.
Have the vehicle checked at an autho-
rized Mercedes-Benz Light Truck
Center.
Compressor
cooling downYou have selected a higher vehicle level.
Due to frequent level changes within a
short period, the compressor must first
cool down.Let the compressor cool until the
message disappears.
The selected level will be set once the
compressor has cooled.
!When the message Compressor cooling
down
appears in the multifunction display,
driving is still possible. Keep in mind that the ride
height of the vehicle is not yet reached, so you
can damage the underbody of the vehicle. The
selected level will be set once the compressor
has cooled.

552 Technical data
Layout of poly-V-belt drive
GL 320 CDI
1Coolant pump
2Idler pulley
3Automatic belt tensioner
4Power steering pump
5Air conditioning compressor
6Crankshaft
7Idler pulley
8Generator (alternator)GL 450
1Idler pulley
2Idler pulley
3Automatic belt tensioner
4Power steering pump
5Air conditioning compressor
6Crankshaft
7Coolant pump
8Generator (alternator)