engine MERCEDES-BENZ R320 2008 W251 Service Manual

146 Controls in detail
Lighting
USA only
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 143).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 178) and “Setting night secu-
rity illumination” (
page 179).Fog lamps
iWith the daytime running lamp mode
activated and the exterior lamp switch in
positionM, you cannot switch on the high
beam headlamps.
The high beam flasher is available at all times.
For nighttime driving, turn the exterior lamp
switch in positionB orU to permit
activation of the high beam headlamps.
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.

148 Controls in detail
Lighting
Push the combination switch in
direction of arrow1 to switch on the
high beam.
The high beam headlamp indicator
lampAin the instrument cluster
comes on (
page 29).
Pull the combination switch in direction
of arrow2 to its original position to
switch off the high beam.
The high beam headlamp indicator
lampAin 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
improve illumination of the area in the
direction 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)Driving forward
Switching on corner-illuminating front
fog lamps
Switch on the left or right turn signal
(
page 59), depending on whether
you are turning left or right.
The respective front fog lamp comes on
and illuminates the area in the
direction into which you are turning.
or
Turn steering wheel in desired direc-
tion.
The front fog lamp on the side of your
steering direction comes on.
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 available.
iIf you have switched on the turn signal for
one side but turn the steering wheel in the
opposite direction, the corner-illuminating front
fog lamp comes on for the side indicated by the
turn signal.
The corner-illuminating front fog lamp remains lit
for a maximum of three minutes. Afterwards, it
goes out even if the turn signal is still switched
on.


151 Controls in detail
Lighting
The controls are located in the overhead
control panel.
Deactivating automatic control
Press switch3.
The interior lighting and the locator
lighting (
page 178) remain switched
off even when you

unlock the vehicle

remove the SmartKey from the
starter switch

open a door

open the tailgateActivating automatic control
Press switch3.
The interior lighting and the locator
lighting (
page 178) come on when
you

unlock the vehicle

remove the SmartKey from the
starter switch

open a door

open the tailgate
The interior lighting switches off after
10 seconds see “Setting interior lighting
delayed shut-off” (
page 180).Manual control
Switching front/rear interior lighting on
and off
Press front/rear interior lighting
switch4 or 2 (
page 150) to switch
on the desired interior light.
Press front/rear interior lighting
switch4 or 2 again to switch off the
respective interior light.
Switching front reading lamps on and off
The front reading lamps are located in the
lower edge of the interior rear view mirror.
Press front reading lamp
switch1or5 (
page 150) to
switch on the desired front reading
lamp.
Press front reading lamp
switch1or5 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 lighting
switches off automatically after approximately
5minutes.

155 Controls in detail
Instrument cluster
Resetting trip odometer
Make sure you are viewing the trip
odometer display (
page 157).
If it is not displayed, press buttonè
orÿ on the multifunction steering
wheel (
page 158) repeatedly until
the trip odometer appears in the multi-
function display.
Press and hold reset button 2
(
page 154) until the trip odometer is
reset.
Tachometer
The red marking on the tachometer
(
page 29) 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 indicated in the
multifunction display (
page 157).
!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
designed to serve as an ice-warning device
and is therefore unsuitable for that purpose.
Indicated temperatures just above the
freezing point do not guarantee that the
road surface is free of ice. The road may still
be icy, especially in wooded areas or on
bridges.

156 Controls in detail
Instrument cluster
The outside temperature sensor is located
in the front bumper area. Due to its loca-
tion, the sensor can be affected by road or
engine heat during idling or slow driving.
This means that the accuracy of the dis-
played temperature can only be verified by
comparison to a thermometer placed next
to the sensor, not by comparison to exter-
nal displays (e.g. bank signs etc.).
When moving the vehicle into colder
ambient 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
temperature indications caused by heat
radiated from the engine during idling or
slow driving.

164 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 buttonkorj to select
the functions in the standard display
menu.The following functions are available:Checking coolant temperature
Press buttonk orj repeatedly
until the coolant temperature appears
in the multifunction display.
FunctionPage
Checking tire inflation pressure373
Checking coolant temperature164
Calling up digital speedometer or
outside temperature165
Calling up maintenance service
indicator402
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.

165 Controls in detail
Control system
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
AUDIO menu
The functions in the
AUDIO menu operate
the audio equipment which you currently
have turned on.
If no audio equipment is currently turned
on, the message
AUDIO off appears in the
multifunction display.
The following functions are available:!Excessive coolant temperature triggers
a warning message in the multifunction
display (
page 448).
The engine should not be operated with a
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 city traffic, the coolant temperature
may rise close to 248°F (120°C).iYou can select whether the digital speed-
ometer or the outside temperature is to be
displayed.
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 175).
FunctionPage
Selecting radio station166
Selecting satellite radio station*166
Operating CD player167

170 Controls in detail
Control system
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 66) 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.The following settings and submenus are
available in the
Settings menu:
iThe vehicle status message memory will
be cleared when you turn the SmartKey in the
starter 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 427).
FunctionPage
Resetting all settings171
Submenus in the Settings menu171
Instrument cluster submenu174
Time/Date submenu176
Lighting submenu177
Vehicle submenu180
Comfort submenu*183

177 Controls in detail
Control system
Lighting submenu
Access the
Lighting submenu via the
Settings menu. Use the Lighting
submenu to change the lamp and lighting
settings on your vehicle.
The following functions are available:Setting daytime running lamp mode
(USA only)
Move the selection marker with
buttonæ orç to the
Lighting
submenu.
Press buttonj ork repeatedly
until the message
Lamp Circuit
Headlamp
appears in the multifunction
display.
The selection marker is on the current
setting.
Press buttonæ orç to select
manual operation (
Manual) or daytime
running lamp mode (
Constant).
With daytime running lamp mode activated
and the exterior lamp switch in
positionM orU, the low beam
headlamps are switched on when the
engine is running.
FunctionPage
Setting daytime running lamp
mode (USA only)177
Setting locator lighting178
Setting night security
illumination179
Setting interior lighting delayed
shut-off180
iThis function is not available in countries
where the daytime running lamp mode is manda-
tory and therefore in a constant mode.

179 Controls in detail
Control system
Setting night security illumination
(Headlamps delayed shut-off feature)
Use this function to set whether you would
like the exterior lamps to remain on for
15 seconds during darkness after exiting
the vehicle and closing all doors.
With the headlamps delayed shut-off
feature activated and the exterior lamp
switch in positionU, the following
lamps will switch on when the engine is
turned off:

Parking lamps

Tail lamps

License plate lamps

Side marker lamps

Front fog lamps
If after turning off the engine you do not
open a door or do not close an opened
door, the lamps will automatically switch
off after 60 seconds.
Move the selection marker with
buttonæ orç to the
Lighting
submenu.
Press buttonj ork repeatedly
until the message
Headlamp Delayed
Shut-off
appears in the multifunction
display.
The selection marker is on the current
setting.
Press buttonæ orç to switch
the headlamps delayed shut-off feature
On or Off.
Turn the exterior lamp switch to
positionU before turning off the
engine.
The headlamps delayed shut-off
feature is activated.You can temporarily deactivate the head-
lamps delayed shut-off feature:
Before exiting the vehicle, turn the
SmartKey in the starter switch to
position0.
Then turn it to position2 and back to
position0.
The headlamps delayed shut-off
feature is deactivated. It will reactivate
as soon as you reinsert the SmartKey in
the starter switch.
Vehicles with KEYLESS-GO*:
Press the KEYLESS-GO* start/stop
button (
page 41).