Page 218 of 521
217 Controls in detail
4-zone automatic climate control*
Canada only1
Air distribution, left
2
Front defroster
3
Temperature rocker switch, left
4
Display
5
Temperature rocker switch, right
6
Rear window defroster
7
Air distribution, right
8
Air distribution and air volume, right
(automatic, manual)
9
AC cooling on/off
a
Rear air-conditioning remote control
b
Increase air volume
c
Climate control on/off
d
Decrease air volume
e
Residual heat/ventilation
f
Air recirculation
g
Air distribution and air volume, left
(automatic, manual)
Page 220 of 521

219 Controls in detail
4-zone automatic climate control*
Nearly all dust particles, pollutants and
odors are filtered out before outside air en-
ters the passenger compartment through
the air distribution system.
The air conditioning will not engage (no
cooling) if the A/Cmode (
page 227) is
deactivated.Deactivating the climate control
system
Deactivating
Press button´ (
page 216) or
(
page 217) until the display4
(page 216) or (
page 217) is
cleared.
Warning!
G
Follow the recommended settings for heat-
ing and cooling given on the following pag-
es. Otherwise the windows could fog up,
impairing visibility and endangering you and
others.
iSevere conditions (e.g. strong air pollu-
tion) may require replacement of the fil-
ter before its scheduled interval. A
clogged filter will reduce the air volume
to the interior.
If the vehicle interior is hot, ventilate
the interior before driving off, see
“Summer opening feature”
(page 234). The climate control will
then adjust the interior temperature to
the set value much faster.
Keep the air intake grille in front of the
windshield free of snow and debris.
Do not obstruct air flow by placing ob-
jects on the air flow-through exhaust
slots below the rear window.
iWhen the climate control system is de-
activated, the outside air supply and
circulation are also deactivated. Only
choose this setting for a short time.
Otherwise the windows could fog up.
Page 221 of 521

220 Controls in detail4-zone automatic climate control*Reactivating
Make sure the ignition is switched on.
Press button´ (
page 216) or
(
page 217) again.
The previous settings are once again in
effect.Operating the climate control system
in automatic modeActivating
Switch on the ignition (
page 36).
Press one buttonU (
page 216) or
(
page 217).
The indicator lamp on the button
comes on.
AUTO
appears in the
display4 (
page 216) or
(
page 217). The air volume and air
distribution are adjusted automatically.
Use temperature controls1 and6
(page 216) or (
page 217) to sepa-
rately adjust the air temperature on
each side of the passenger compart-
ment.
The temperature of the vehicle interior
is adjusted automatically.
iTo switch the system on, you can also
press another button, with the excep-
tion of 1, F and T
(page 216) or (
page 217).
iWhen operating the climate control
system in automatic mode, you will
only rarely need to adjust the tempera-
ture, air volume and air distribution.
In automatic mode, cooling with dehu-
midify is switched on. This function can
be switched off if necessary.iThe automatic climate control system
can also be switched on or off
separately for the left and right sides of
the passenger compartment, as
required.
Page 224 of 521

223 Controls in detail
4-zone automatic climate control*
Adjusting air volume
Use buttonsU (
page 216) or
(
page 217) for automatic mode or air
volume buttons orQ
(page 216) or (
page 217) to adjust air
volume manually.
Nine blower speeds are available.
Press button to decrease or
buttonQ to increase air volume to
the desired level.
The indicator lamps on the
buttonsU go out.
AUTO
disappears
in the display4 (
page 216) or
(
page 217) and the automatic mode
is switched off. The selected blower
speed is shown in the display4.
Front defroster
You can use this setting to defrost the
windshield, for example if it is iced up.
You can also defog the windshield and the
side windows.
Activating
Press buttonP or 0
(page 216) or (
page 217).
The indicator lamp on the button
comes on. Display4 (
page 216) or
(
page 217) is cleared.The air conditioning switches
automatically to the following functions:
cooling on to dehumidify
maximum blowing and heating
power (depends on cooling
temperature)
air flows onto the windshield and
the front side windows
the air recirculation mode is
switched off
Deactivating
Press buttonPor 0
(page 216) or (
page 217) again.
The indicator lamp on the button goes
out. Defrosting is turned off.
The previous settings are once again in
effect.
iKeep this setting selected only until the
windshield or the side windows are
clear again.
iThe cooling remains switched on.
Page 225 of 521

224 Controls in detail4-zone automatic climate control*Windshield fogged on the outside
Switch the windshield wipers on
(page 56).
Press one buttonU (
page 217) or
(
page 216).
The indicator lamp on the button
comes on.
AUTO
appears in the
display4 (
page 216) or
(
page 217). The air volume and air
distribution are adjusted automatically.
If the automatic mode of the climate con-
trol is switched off:
Turn air distribution control1 and 7
to a or Y (
page 216) or
(
page 217).
Maximum cooling MAX COOL
If the left and right air distribution controls
as well as the airflow volume control are
set toU and there is a high need for
cooling, the display “
MAX COOL
” appears in
the front and rear display (
page 229).
This provides the fastest possible cooling
of the vehicle interior (when windows and
tilt/sliding sunroof* or tilt/sliding panel*
are closed).
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.
iKeep this setting selected only until the
windshield is clear again.
Warning!
G
Fogged windows impair visibility, endanger-
ing 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 window
fogging persists, make sure the air
conditioning (
page 227) is activated, or
press buttonP or0.
Page 228 of 521

227 Controls in detail
4-zone automatic climate control*
Air conditioning
The cooling function, only operational
when the engine is running, cools the vehi-
cle interior down to the selected tempera-
ture. The cooling function also
dehumidifies the air in the vehicle interior,
thus preventing the windows from fogging
up.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 button2 (
page 216) or
(
page 217).
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 button2 (
page 216) or
(
page 217) 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.
iCondensation may drip out from under-
neath the vehicle. This is normal and
not an indication of a malfunction.Warning!
G
If you turn off the cooling function, the
vehicle will not be cooled when weather
conditions are warm. The windows can fog
up more quickly. Window fogging may
impair visibility and endanger you and
others.
!If the air conditioning cannot be turned
on again, this indicates that the air con-
ditioning is losing refrigerant. The com-
pressor has turned itself off.
Have the air conditioning checked at
the nearest authorized Mercedes-Benz
Center.
Page 326 of 521

325 Operation
Engine compartment
Coolant level
The engine coolant is a mixture of water
and anticorrosion/antifreeze. To check
the coolant level, the vehicle must be
parked on level ground and the engine
must be cool.
The coolant expansion tank is located on
the driver’s side of the engine compart-
ment.
1Coolant expansion tank
Using a rag, turn the cap slowly approx-
imately one half turn to the left to re-
lease any excess pressure.
Continue turning the cap to the left and
remove it.
The coolant level is correct if the level:
for cold coolant: reaches the black
top part of the reservoir
for warm coolant: is approximately
0.6 in (1.5 cm) higher
Add coolant as required.
Replace and tighten cap.
For more information on coolant, see the
“Technical data” section (
page 490).
Warning!
G
In order to avoid any possibly serious burns:
Use extreme caution when opening the
hood if there are any signs of steam or
coolant leaking from the cooling system,
or if the coolant temperature gauge indi-
cates that the coolant is overheated.
Do not remove pressure cap on coolant
reservoir if coolant temperature is
above 158°F (70°C). Allow engine to
cool down before removing cap. The
coolant reservoir contains hot fluid and
is under pressure.
Do not spill antifreeze on hot engine
parts. Antifreeze contains ethylene gly-
col which may burn if it comes into con-
tact with hot engine parts.
Using a rag, slowly open the cap approx-
imately
1/2 turn to relieve excess pres-
sure. If opened immediately, scalding
hot fluid and steam will be blown out un-
der pressure.
Page 380 of 521

379 Practical hints
What to do if …
Problem
Possible cause/consequence
Suggested solution
D
The red coolant warning lamp
comes on when the engine is
running.
There is insufficient coolant in the reservoir.
If this warning lamp comes on frequently,
there is a leak in the cooling system.
If the coolant level is correct, the electric ra-
diator fan may be broken.
Immediately add coolant to prevent
engine from overheating
(page 325).
Have the cooling system checked.
If the coolant temperature is below
257°F (125°C), you can continue
driving to the nearest authorized
Mercedes-Benz Center.
Avoid high engine loads (e.g. driving
uphill) and stop-and-go driving.
The red coolant warning lamp
comes on while driving and you
hear a warning sound.
The coolant temperature has exceeded
257°F (125°C).
Stop as soon as possible in a safe lo-
cation and allow the engine and cool-
ant to cool down.
Warning!
G
Driving when your engine is badly overheat-
ed 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 and can occur just by opening
the engine hood. Stay away from the engine
if you see or hear steam coming from it.
Turn off the engine, get out of the vehicle
and do not stand near the vehicle until the
engine has cooled down.