2008 MERCEDES-BENZ GL550 engine

146 Controls in detail
Lighting
When the engine is running, and you turn
the exterior lamp switch to positionC
orB, the manual headlamp mode has
priority over the daytime running lamp
mode.
The corresponding exterior lamps switch
on (
page 61).
Locator lighting and night security
illumination
The locator lighting and the night security
illumination are described in the “Control
system” section, see “Setting locator light-
ing” (
page 176) and “Setting night secu-
rity illumination” (
page 176).Fog lampsFront fog lamps
Turn the exterior lamp switch to
positionC orB (
page 144).
Pull out the exterior lamp switch to first
stop.
The front fog lamps switch on.
The green indicator lamp‡ in the
exterior lamp switch comes on.
Push in the exterior lamp switch.
The front fog lamps switch off.
The green indicator lamp‡ in the
exterior lamp switch goes out.
Rear fog lamp (driver’s side only)
Turn the exterior lamp switch to
positionB (
page 144).
Pull out the exterior lamp switch to
second stop.
The rear fog lamp switches on.
The yellow indicator lamp† in the
exterior lamp switch comes on.
Warning!G
In low ambient lighting or foggy conditions,
only switch from positionU toB with
the vehicle at a standstill in a safe location.
Switching fromU toB will briefly
switch off the headlamps. Doing so while
driving in low ambient lighting conditions
may result in an accident.
iFog lamps will operate with the parking
lamps and/or the low beam headlamps on. Fog
lamps should only be used in conjunction with
low beam headlamps. Consult your State or
Province Motor Vehicle Regulations regarding
permissible lamp operation.
iFog lamps cannot be switched on with the
exterior lamp switch in positionU.
To switch on the fog lamps, turn the exterior
lamp switch to positionB first.
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147 Controls in detail
Lighting
Push in the exterior lamp switch to first
stop.
The rear fog lamp switches off.
The yellow indicator lamp† in the
exterior lamp switch goes out.
The front fog lamps remain lit.
Combination switch
1High beam
2High beam flasherHigh beam
Turn the exterior lamp switch to
positionB (
page 143).
Push the combination switch in
direction of arrow1 to switch on the
high beam.
The high beam headlamp indicator
lampA in the instrument cluster
comes on (
page 26).
Pull the combination switch in direction
of arrow2 to its original position to
switch off the high beam.
The high beam headlamp indicator
lampA in the instrument cluster
goes out.
High beam flasher
Pull the combination switch briefly in
direction of arrow2.
Corner-illuminating front fog lamps*
The corner-illuminating front fog lamps im-
prove illumination of the area in the direc-
tion into which you are turning.
The corner-illuminating front fog lamps will
operate with the engine running and with

the exterior lamp switch in
positionB (
page 143)
or

the exterior lamp switch in
positionU (
page 143)
or

the daytime running lamp mode
activated (
page 145)
iThe corner-illuminating front fog lamps will
only come on in low ambient lighting conditions.
iIf you are driving faster than 25 mph
(40 km/h) or have the front fog lamps switched
on, the corner-illuminating function is not avail-
able.
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150 Controls in detail
Lighting
Automatic control
Deactivating
Press switch3.
The switch engages in the recessed
position.
The interior lighting and the locator
lighting (
page 176) remain switched
off even when you

unlock the vehicle

open a door

open the tailgate

remove the SmartKey from the
starter switchActivating
Press switch3.
The switch disengages from its
recessed position back to its original
position.
The interior lighting and the locator
lighting (
page 176) come on when
you

unlock the vehicle

open a door

open the tailgate

remove the SmartKey from the
starter switch
The interior lamps go out following an
adjustable time delay (
page 177).Manual control
Switching front/rear interior lighting on
and off
Press front/rear interior lighting
switch4 or2 to switch on the
respective interior light.
Press front/rear interior lighting
switch4 or2 again to switch off the
respective interior light.
Switching front reading lamps on and off
Press front reading lamp switch1
or5 to switch on the respective front
reading lamp.
Press front reading lamp switch1
or5 again to switch off the respective
front reading lamp.
!An interior lamp switched on manually does
not go out automatically.
Leaving an interior lamp switch in the ON
position for extended periods of time with the
engine turned off could result in a discharged
battery.
iThe interior lighting is factory-set to
automatic mode.
iIf a door remains open, the interior lamps
switch off automatically after approximately
5 minutes when the SmartKey is removed or in
starter switch position0.
iAn interior lamp switched on manually does
not go out automatically.
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153 Controls in detail
Instrument cluster
Adjusting instrument cluster illumina-
tion
Use button1 or3 to adjust the illumina-
tion brightness for the instrument cluster.
To brighten illumination
Press and hold button3 until the
desired level of illumination is reached.
To dim illumination
Press and hold button1 until the
desired level of illumination is reached.
Resetting trip odometer
Make sure you are viewing the trip odome-
ter display (
page 155).
If it is not displayed, press buttonè
orÿ on the multifunction steering
wheel (
page 156) repeatedly until
the trip odometer appears in the multi-
function display.
Press and hold reset button2 in the
instrument cluster (
page 152) until
the trip odometer is reset.
Tachometer
The red marking on the tachometer
(
page 26) denotes excessive engine
speed.To help protect the engine, the fuel supply
is interrupted if the engine is operated
within the red marking.
Outside temperature indicator
The outside temperature is displayed in the
multifunction display (
page 155).
iThe instrument cluster illumination is
dimmed or brightened automatically to suit am-
bient light conditions.
The instrument cluster illumination will also be
adjusted automatically when you switch on the
vehicle’s exterior lamps.
iWith the exterior lighting switched on, the
brightness of the switches in the center console
will also be adjusted when using button
1 or3.
!Avoid driving at excessive engine speeds, as
it may result in serious engine damage that is not
covered by the Mercedes-Benz Limited
Warranty.
Warning!G
The outside temperature indicator is not de-
signed to serve as an ice-warning device and
is therefore unsuitable for that purpose.
Indicated temperatures just above the freez-
ing point do not guarantee that the road sur-
face is free of ice. The road may still be icy,
especially in wooded areas or on bridges.
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154 Controls in detail
Instrument cluster
The temperature sensor is located in the
front bumper area. Due to its location, the
sensor can be affected by road or engine
heat during idling or slow driving. This
means that the accuracy of the displayed
temperature can only be verified by com-
parison to a thermometer placed next to
the sensor, not by comparison to external
displays (e.g. bank signs etc.).
When moving the vehicle into colder ambi-
ent temperatures (e.g. when leaving your
garage), you will notice a delay before the
lower temperature is displayed.
A delay also occurs when ambient temper-
atures rise. This prevents inaccurate tem-
perature indications caused by heat
radiated from the engine during idling or
slow driving.
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162 Controls in detail
Control system
Standard display menu
In the standard display, the main odometer
and the trip odometer appear in the multi-
function display.
1Trip odometer
2Main odometer
If you see another display, press
buttonè orÿ repeatedly until
the standard display appears.
Press buttonk orj to select
the functions in the standard display
menu.The following functions are available:Checking coolant temperature
FunctionPage
Checking tire inflation pressure395
Checking coolant temperature162
Calling up digital speedometer
or outside temperature163
Calling up maintenance service
indicator424
Warning!G

Driving when your engine is overheated
can cause some fluids which may have
leaked into the engine compartment to
catch fire. You could be seriously
burned.

Steam from an overheated engine can
cause serious burns which can occur
just by opening the hood. Stay away
from the engine if you see or hear steam
coming from it.
Stop the vehicle in a safe location away from
other traffic. Turn off the engine, get out of
the vehicle and do not stand near the vehicle
until the engine has cooled down.
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163 Controls in detail
Control system
Press buttonk orj repeatedly
until the coolant temperature appears
in the multifunction display.Calling up digital speedometer or
outside temperature
Press buttonk orj repeatedly
until the digital speedometer or the
outside temperature appears in the
multifunction display.
Digital speedometer
Outside temperature
!Excessive coolant temperature triggers a
warning message in the multifunction display
(
page 470).
The engine should not be operated with the
coolant temperature above 248°F (120°C).
Doing so may cause serious engine damage
which is not covered by the Mercedes-Benz
Limited Warranty.
iDuring severe operating conditions, e.g.
stop-and-go traffic, the coolant temperature may
rise close to 248°F (120°C).
iYou can select whether the digital speedom-
eter or the outside temperature is shown in the
multifunction display.
You can change the setting in the submenu
Instrument Cluster via the function Status
Line Display
, see “Selecting display (digital
speedometer or outside temperature) for status
indicator” (
page 173).
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168 Controls in detail
Control system
If conditions have occurred causing status
messages to be recorded, the number of
messages appears in the multifunction
display:
Press buttonk orj.
The stored messages will now be
displayed in the order in which they
have occurred. For malfunctions and
warning messages, see “Vehicle status
messages in the multifunction display”
(
page 449).Should the vehicle’s system record any
conditions while driving, the number of
messages will reappear in the multifunc-
tion display

when the SmartKey in the starter
switch is turned to position0 or
removed from the starter switch.
or

when you turn off the engine by
pressing the KEYLESS-GO* start/stop
button (
page 69) in the starter
switch once and open the driver’s door
(this puts the starter switch in
position0, same as with the SmartKey
removed from the starter switch)
Settings menu
In the
Settings menu there are two
functions:

The function Reset to factory
settings?
, with which you can reset all
the settings to the original factory
settings.

A collection of submenus with which
you can make individual settings for
your vehicle.
Press buttonè orÿ repeatedly
until the
Settings menu appears in the
multifunction display.
iAfter you have scrolled through all recorded
status messages, the first recorded message
appears again.
iThe vehicle status message memory will be
cleared when you turn the SmartKey in the start-
er switch to position1 or2, or when you press
the KEYLESS-GO* start/stop button once or
twice without depressing the brake pedal. You
will then only see high priority messages in the
multifunction display (
page 449).
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