Mercedes-Benz 2008 R 320 CDI 4MATIC Operator's Manual page 128

The switches are located in the driver's
door.
1 Central unlocking switch
2 Central locking switch
Locking
Press central locking switch 2.
If all doors and the tailgate are closed,
the vehicle locks.
Unlocking
Press central unlocking switch 1.
The vehicle unlocks.
i
You can open a locked door from the inside
at any time. Open door only when conditions are
safe to do so.
If the vehicle was previously centrally locked
with the SmartKey or with KEYLESS-GO*, it will
not unlock using the central unlocking switch.
If the vehicle was previously locked with the
central locking switch:
and the SmartKey or SmartKey with
KEYLESS-GO* is set to factory settings, the
complete vehicle is unlocked when a front
door is opened from the inside
and the SmartKey or SmartKey with
KEYLESS-GO* is set to selective settings,
only the front door opened from the inside is
unlocked
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With the passenger-side door opened, you
cannot lock the vehicle with the central locking
switch.
Controls in detail
Locking and unlocking
127