Chevrolet 1998 Lumina Owner's Manual page 114

If you open a door, the lamps will stay on while it's
open and then turn off automatically about 18 seconds
after you close it. If you don't open a door, the lamps
will turn off after about 18 seconds, unless you press
UNLOCK or the trunk symbol on the remote keyless
entry transmitter. If you press UNLOCK or the trunk
symbol and don't open a door, the lamps will turn off
after about 55 seconds. If you press LOCK on the
remote keyless entry transmitter the lamps will turn off
about 17 seconds after all the doors are closed.
Sustained interior illumination includes a feature called
theater dimming. With theater dimming, the lamps don't
just turn off at the end of the delay time. Instead, they
slowly dim during the delay time until they go out. The
delay time is canceled if you turn the ignition key
to
RUN or START, so the lamps will go out right away.
When the ignition is on, sustained interior illumination
is inactive, which means the courtesy lamps won't
come on.
Rearview Mirror Reading Lamps
These lamps go on when you open the doors. When
the doors
are
closed, turn
the
lamps on and uff with
the switches.
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