2008 MERCEDES-BENZ C300 4MATIC Owner's Manual

424 Practical hints
Unlocking/locking in an emergency
Unlocking the vehicle
If you cannot unlock the vehicle with the
SmartKey or KEYLESS-GO* (Canada only),
unlock the driver’s door and the trunk us-
ing the mechanical key. Removing the mechanical key
1Mechanical key locking tab
2Mechanical key
Move locking tab1 in the direction of
arrow.
Slide mechanical key2 out of the
housing.Unlocking the driver’s door
Insert mechanical key2 into the driv-
er’s door lock until it stops.
Turn mechanical key2 counterclock-
wise to position 1.
The locking knob moves up, the driver’s
door is unlocked.
Pull the door handle to open the driv-
er’s door.
iUnlocking the vehicle with the mechanical
key and opening the driver’s door or the trunk
with the mechanical key will trigger the anti-theft
alarm system (
page 66).
To cancel the alarm, insert the SmartKey or
SmartKey with KEYLESS-GO* (Canada only) in
the starter switch.
1Unlocking
2Mechanical key

425 Practical hints
Unlocking/locking in an emergency
Unlocking the trunk
A minimum height clearance of 5.9 ft
(1.90 m) is required to open the trunk lid.
Insert the mechanical key2 into the
trunk lid lock until it stops.
Turn mechanical key2 all the way
counterclockwise to position 2.
The trunk opens.
Turn the mechanical key2 back and
remove it from the trunk lid lock.
Locking the vehicle
If you cannot lock the vehicle with the
SmartKey or KEYLESS-GO* (Canada only),
do the following:
Close the front passenger door, the
rear doors and the trunk.
Open the driver’s door.
Press the central locking switch on the
driver’s door (
page 81).
The locking knobs of the front passen-
ger door and the rear doors move
down.
If the vehicle battery is disconnected or
drained:
Press down the locking knobs of
the front passenger door and the
rear doors manually.
Exit the vehicle.
Close the driver’s door.
Use the mechanical key2 to lock the
vehicle from the outside via the driver's
door. Turn the mechanical key2 to
position1.
The locking knob of the driver’s door
moves down. The vehicle is locked.
Check whether the doors and the trunk
are locked.
If necessary, lock the trunk with the
mechanical key2 (
page 272).
1Unlocking in an emergency
2Mechanical key
!The trunk lid swings open upwards automat-
ically. Always make sure there is sufficient over-
head clearance.
1Locking
2Mechanical key


426 Practical hints
Unlocking/locking in an emergency
Fuel filler flap
Open the fuse box in the trunk
(
page 458).
1Release cable
Pull on the release cable1.
Open the fuel filler flap.Manually unlocking the transmission
gear selector lever
In case of power failure, the transmission
gear selector lever can be manually un-
locked, e.g. to tow the vehicle.
1Selector lever cover
2Unlocking mechanism
Apply the parking brake firmly.
Push the selector lever cover1 to the
left and pull it up and off.
Push the unlocking mechanism2
down and move the selector lever out
of positionP at the same time.The selector lever can now move freely
until reset to positionP.
iThis procedure does not arm the anti-theft
alarm system nor does it lock the fuel filler flap.
iThe gear selector lever is locked again when
moving it to positionP.


427 Practical hints
Resetting activated head restraints
Resetting activated head restraints
If the active head restraints (front seats)
have been triggered in an accident, the ac-
tive head restraints must be reset. Other-
wise, the active head restraints cannot
offer any additional protection in the event
of another rear-end collision.
You can tell that the head restraints have
been triggered when they have been
moved forward and cannot be adjusted.
1Fold back
2Push back
3Push downPush the head restraint cushion by the
bottom, back as far as it will go2.
Push the head restraint cushion down
into the guide as far as it will go3.
Fold the head restraint cushion by the
top, back firmly until it engages1.
Repeat this procedure on the active
head restraints for second head re-
straint.
For information on active head restraints,
see “Active head restraints” (
page 50).
For information on head restraint adjust-
ment, see “Adjusting rear head restraints”
(
page 89).
Warning!G
For safety reasons, have the active head
restraints checked at an authorized
Mercedes-Benz Center after a rear-end
collision.
Warning!G
When pushing back the head restraint cush-
ion, take care that your fingers do not be-
come caught between the head restraint
cushion and the cover. Failing to do so may
lead to injury.
iFor your convenience, we recommend that
you have this work carried out at an authorized
Mercedes-Benz Center.

428 Practical hints
Replacing SmartKey batteries
If the batteries in the SmartKey/SmartKey
with KEYLESS-GO* are discharged, the ve-
hicle can no longer be locked or unlocked.
It is recommended to have the batteries re-
placed at an authorized Mercedes-Benz
Center.Batteries contain materials that can harm
the environment if disposed of improperly.
Recycling of batteries is the preferred
method of disposal. Many states require
sellers of batteries to accept old batteries
for recycling.
Replacement batteries: Lithium, type
CR 2025 or equivalent.
Remove the mechanical key from the
SmartKey (
page 424).1Mechanical key
2Battery compartment
Insert mechanical key 1 into opening.
Press mechanical key 1 in direction of
arrow.
The battery compartment is unlatched.
Pull battery compartment 2 out of the
housing.
Warning!G
Batteries contain poisonous and corrosive
substances. Therefore keep the batteries
out of reach of children.
If a battery is swallowed, seek medical help
immediately.
Warning!G
SmartKey batteries contain Perchlorate
material, which may require special handling
and regard for the environment. Check with
your local government’s disposal guidelines.
California residents, see
http://www.dtsc.ca.gov/HazardousWaste
/Perchlorate/index.cfm.
iWhen replacing batteries, make sure they
are clean and free of lint.
iWhen replacing batteries, always replace
both batteries. The required replacement batter-
ies are available at any authorized
Mercedes-Benz Center.

429 Practical hints
Replacing SmartKey batteries
3Batteries
4Contact springs
Pull out batteries3.
Using a line-free cloth, insert new bat-
teries 3 under contact springs 4 with
the positive terminal (+) side facing up.
Return battery compartment 2 into
housing until it locks into place.
Slide the mechanical key back into the
SmartKey.
Check the operation of the SmartKey
or SmartKey with KEYLESS-GO*.

430 Practical hints
Replacing bulbs
Safe vehicle operation depends on proper
exterior lighting and signaling. It is there-
fore essential that all bulbs and lamp
assemblies are in good working order at all
times.Correct headlamp adjustment is extremely
important. Have headlamps checked and
readjusted at regular intervals and when a
bulb has been replaced. See an authorized
Mercedes-Benz Center for headlamp
adjustment.iIf the headlamps or front fog lamps are
fogged up on the inside as a result of high
humidity, driving the vehicle a distance with the
lights on should clear up the fogging.
iBackup bulbs will be brought into use when
lamps malfunction. Read and observe the mes-
sages in the multifunction display (
page 413).

431 Practical hints
Replacing bulbs
Bulbs Front lamps Rear lamps
LampType
1Additional turn signal
lampLED
2Turn signal lampPY 21 W
3Halogen headlamp:
Low beam
Bi-Xenon* headlamp:
Low and high beam
1
1Regarding vehicles with Bi-Xenon headlamps*, do
not replace the Bi-Xenon bulbs yourself.
H7 (55 W)
D1S-35 W
4Halogen headlamp:
High beam/high beam
flasher
Bi-Xenon* headlamp:
High beam flasher
H7 (55 W)
H7 (55 W)
5Front fog lamp
Corner-illuminating
front fog lamp*H11 (55 W)
H11 (55 W)
6Side marker lampW 5 W
7Parking and standing
lamp2 x
W5W-BV
LampType
8High mounted brake
lampLED
9Side markerW 5 W
aTurn signal lampPY 21 W
bBrake lamp, parking
and standing lamp, tail
lamp2 x P 21 W
cBackup lampP 21 W
dLicense plate lampsW 5 W
eRear fog lamp
(driver’s side only),
Side markerP 21 W
W 5 W