Buick 1998 Century Owner's Manual page 121

Dome Lamp
The dome lamp will come on when you open the doors.
Battery Rundown Protection
Your vehicle has a feature to help prevent you from
draining the battery in case you accidentally leave the
interior courtesy lamps, reading/map lamps, visor vanity
lamps, trunk lamp, underhood lamp or glove box lamps
on. If you leave any of these lamps on, they will
automatically turn off after 20 minutes, if the ignition is
in OFF. The lamps won't come back on again until you:
Turn the ignition on,
Turn the lamp switch off, then on; or
Open a door.
Note that if your vehicle has less than 15 miles (25 km)
on the odometer, the battery saver will turn off the lamps
after only three minutes.
Retained Accessory Power (If Equipped)
With retained accessory power, your power windows,
audio system and sunroof will continue to work up to
10 minutes after the ignition key is turned to OFF and
none of the doors are opened.
Mirrors
Adjust all the mirrors so you can see clearly when you
are sitting in a comfortable driving position.
Inside Day/Night Rearview Mirror
To reduce glare from lamps behind you, pull the lever at
the bottom of the mirror toward you (to the night
position). To return the mirror back to the day position,
push the lever away from you.