2008 MERCEDES-BENZ GL550 heating

225 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 216).
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 216) 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 216).
The indicator lamp on the button
comes on.
Deactivating
Press button9 (page 216).
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
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226 Controls in detail
Climate control
Rear climate control*
The control panel is located on the rear of
the front center console.
Activating rear climate control
Press buttonU.
The indicator lamp on the button
comes on. The air volume and air distri-
bution are adjusted automatically.Deactivating rear climate control
Press button´.
The indicator lamp on the button
comes on.
The cooling function switches off after
a short delay.iThe rear climate control panel is only
available if your vehicle is equipped with seat
heating* for the rear seats or Rear Audio fea-
ture* (see separate COMAND System operating
instructions).
1Left rear center air vent, adjustable
2Right rear center air vent, adjustable
3Rear climate control on
(automatic mode)
4Air distribution (directs air through
the center air vents)
5Air distribution (directs air through
the footwells and side air vents)
6Rear air conditioning off
iThe climate control must be switched on
(
page 227).
iThe temperature is adjusted according to
the settings for the front passenger side made
on the front climate control panel (
page 219).
iSwitch off the rear climate control for im-
proved cooling or heating output in the front pas-
senger compartment.
You can also switch off the rear climate control
from the front passenger compartment
(
page 227).
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236 Controls in detail
3-zone automatic climate control*
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
front 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 front door windows.
Press button
to decrease or
buttonQ to increase air volume
(
page 230) 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 button|
goes out. The indicator lamp on
button9 comes on.
or
Turn temperature control1
and/or7 (
page 230) slightly in any
direction.
Heating switches to the temperature
that was set before the front defroster
was switched on.
The indicator lamp on button|
goes out. The indicator lamp on
button9 comes on.Deactivating
Press button| (page 230).
The indicator lamp on the button goes
out. Defrosting is turned off.
The previous settings are once again in
effect.
iThe air conditioning compressor remains on
even if the indicator lamp in button| goes
out. This helps to prevent the windshield from
fogging.
iTo switch off, you can also press
button´ orU (
page 230).
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241 Controls in detail
3-zone automatic climate control*
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 41).
Press button9 (page 230).
The indicator lamp on the button
comes on.
Deactivating
Press button9.
The indicator lamp on the button goes
out.
Rear automatic climate control
The control panel is located at the rear of
the front center console.
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.
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
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242 Controls in detail
3-zone automatic climate control*
Activating rear automatic climate
control
Press buttonU.
The indicator lamp on the button
comes on. The temperature, air vol-
ume, and air distribution are adjusted
automatically.
Deactivating rear automatic climate
control
Press button´.
The indicator lamp on the button goes
out.
The cooling function switches off after
a short delay.Operating from the front
Deactivating
Press button> (page 230).
The indicator lamp on the button goes
out.
In displaye (
page 230), you will see
the> symbol followed by
MODE for
approximately 3 seconds.
Press button´ (page 230).
In displaye (
page 230), you will see
the> symbol followed by
OFF.
The rear automatic climate control is
switched off.
1Left rear center air vent, adjustable
2Right rear center air vent, adjustable
3Temperature control
4Air distribution and air volume
(automatic, manual)
5Air distribution (directs air through
the center air vents)
6Air distribution (directs air through
the footwells and side air vents)
7Rear automatic climate control
on/off
8Decreasing air volume
9Indicator lamps for air volume
settings
aIncreasing air volume
iThe stored values for the rear automatic
climate control are erased from memory after
the ignition has been switched off for more than
30 minutes. Once the front automatic climate
control is switched on again, the rear automatic
climate control operates in automatic mode at a
preset temperature of 72°F (22°C).
iThe automatic climate control must be
switched on (
page 233).
iSwitch off the rear automatic climate con-
trol for improved cooling or heating output in the
front passenger compartment.
You can also switch off the rear automatic
climate control from the front passenger com-
partment (
page 230).
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323 Controls in detail
Useful features
Cigarette lighter
Depending on vehicle configuration your
vehicle is equipped with a cigarette lighter
and an ashtray (
page 321) located in the
front center console and an ashtray locat-
ed in front of the second-row seats
(
page 322).
Switch on the ignition (page 42).
1Cigarette lighter
Open the ashtray (page 322).
Push in cigarette lighter1.
The cigarette lighter will pop out auto-
matically when hot.
Warning!G
Never touch the heating element or sides of
the cigarette lighter; they are extremely hot.
Hold the knob only.
Make sure that any children traveling with
you do not injure themselves or start a fire
with the hot cigarette lighter.
When leaving the vehicle always remove the
SmartKey or SmartKey with KEYLESS-GO*
from the starter switch, take it with you, and
lock the vehicle. Do not leave children unat-
tended in the vehicle, or with access to an
unlocked vehicle. A child’s unsupervised
access to a vehicle could result in an
accident and/or serious personal injury.
!The lighter socket can accommodate
12V DC electrical accessories (up to a maximum
of 180 W) designed for use with the standard
“cigarette lighter” plug type. Keep in mind, how-
ever, that connecting accessories to the lighter
socket (for example extensive connecting and
disconnecting, or using plugs that do not fit prop-
erly) can damage the lighter socket. With the
socket damaged, the lighter may no longer be
able to be placed in the heating (pushed-in) posi-
tion, or the lighter may pop out too early with the
lighter not hot enough.
To help avoid damaging the cigarette lighter
socket, we recommend connecting 12V DC elec-
trical accessories designed for use with the stan-
dard “cigarette lighter” plug type to the 12V
power outlets (
page 324) in your vehicle
whenever possible.
iIf the engine is off, and the cigarette lighter
is being used extensively, the vehicle battery
may become discharged.
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327 Controls in detail
Useful features
Heated steering wheel*
The steering wheel heating warms up the
leather area of the steering wheel.
The stalk is on the lower left-hand side of
the steering wheel.
1Switching on
2Indicator lamp
3Switching offSwitching on
Switch on the ignition (page 42).
Turn switch at the tip of stalk in the
direction of arrow1.
The steering wheel is heated. Indicator
lamp2 comes on.Switching off
Turn switch at the tip of stalk in the
direction of arrow3.
The heated steering wheel is switched
off. Indicator lamp2 goes out.
For information on the steering wheel, see
“Multifunction steering wheel”
(
page 30).
iThe steering wheel heating is turned off tem-
porarily and the indicator lamp2 remains on
when

the temperature of the vehicle interior is
above 86°F (30°C)

the temperature of the steering wheel is
above 95°F (35°C)
When these conditions do not apply anymore,
steering wheel heating continues.
iIndicator lamp2 flashes or goes out

in case of power surge or undervoltage

in case of a steering wheel heating malfunc-
tion
iThe steering wheel heating switches off
automatically when you remove the SmartKey
from the starter switch or, on vehicles with
KEYLESS-GO*, when you switch off the ignition
(
page 41) and open the driver’s door.
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348 Operation
Driving instructions
Power assistanceBrakes
Warning!G
With the engine not running, there is no
power assistance for the brake and steering
systems. In this case, it is important to keep
in mind that a considerably higher degree of
effort is necessary to brake and steer the ve-
hicle.
Warning!G
After driving in heavy rain for some time
without applying the brakes or through wa-
ter deep enough to wet brake components,
the first braking action may be somewhat re-
duced and increased pedal pressure may be
necessary to obtain expected braking ef-
fect. Maintain a safe distance from vehicles
in front.
Resting your foot on the brake pedal will
cause excessive and premature wear of the
brake pads.
It can also result in the brakes overheating,
thereby significantly reducing their effec-
tiveness. It may not be possible to stop the
vehicle in sufficient time to avoid an acci-
dent.
!Operational or performance test must only
be conducted on a two-axle dynamometer. If
such tests are necessary, contact an authorized
Mercedes-Benz Light Truck Center. You could
otherwise seriously damage the brake system or
the transfer case which is not covered by the
Mercedes-Benz Limited Warranty.
!Because the ESP® operates automatically,
the engine and ignition must be shut off
(SmartKey in starter switch position0 or1 or
KEYLESS-GO* start/stop button in
position0or1) when testing the parking brake
on a brake test dynamometer and such testing
should be no longer than 10 seconds.
Active braking action through the ESP
® may
otherwise seriously damage the brake system
which is not covered by the Mercedes-Benz
Limited Warranty.
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