Mercedes-Benz 500 SEC Operator's Manual page 46

Seat Belt Extender
When the respective door is closed and
the key is in steering lock position 1 or
2, the seat belt extender brings the belt
forward within easy reach of the
occupant.
The seat belt extender also brings the
belt forward, if the seat is not occupied.
Switch on center console
With the doors closed and seat belt not
buckled, the seat belt extender can also
be brought forward by using the switch.
If the seat belt is not buckled within 30
seconds, the seat belt extender will
return to its rest position.
This is also the case if the key is turned
to steering lock position 1 or if a door is
opened.
For safety reasons, avoid adjusting the
seat or seat back into positions which
could affect the correct seat belt
position.
Warning!
The seat belt extender must be in its
rest position for the seat belt to
provide proper protection. If the
electrical system fails, forcibly push
the extender back to its rest position.
If the seat belt extender cannot be
brought to its rest position, the seat
belt cannot provide proper protection
in case of an accident.
In this case have the system checked
at your authorized Mercedes-Benz
dealer.
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