BMW 5 series Owner's Manual page 61

Locking the doors and
windows
Rear doors
Push the locking lever on the rear doors down.
The door can now be opened from the outside
only.
Safety switch for the rear
Press the button on the driver's door if
children are being transported in the
rear.
This locks various functions so that they cannot
be operated from the rear: safety switch, refer to
page 44.
Online Edition for Part no. 01 40 2 903 008 - 07 12 490
Transporting children safely Controls
61