Mercedes-Benz 190E 2.3 1987 Owner's Manual page 40

Operation:
The inertia reel stops the belt from
unwinding during sudden vehicle
stops or when quickly pulling on the
belt.
The emergency tensioning retractor
tightens the seat belt upon severe
frontal impacts within the shaded area
shown on page 39.
The locking function of the reel may
be checked by quickly pulling out the
belt.
38
Lap belt for middle of rear seat:
Pull belt with latch plate (1) across the
lap, press latch plate into buckle (2)
until it clicks. The belt must not be
twisted and must be tight.
To shorten the belt: with the latch
plate engaged, pull the loose end of
the belt.
To lengthen the belt: with the belt un­
fastened, turn the latch plate so that it
is a little more than 90° to the belt,
then extend the belt. Fasten the belt
and shorten as stated above.
To disengage the belt, push red
button (3) in buckle.