Toyota Lexusc Owner's Handbook Manual page 281

STEERING WHEEL AND MIRRORS
Adjust the mirror so that you can just see the rear of your
vehicle in the mirror.
Type A — Pushing the "AUTO" switch and "OFF" switch
change the mode between AUTO and DAY.
Type B — Pushing the "MIRROR" switch changes the
mode between AUTO and DAY.
The indicator comes on when the AUTO mode is selected.
DAY mode: The mirror surface is normal.
AUTO mode: If the mirror detects light from the headlights
of the vehicle behind you, the mirror surface darkens
slightly to reduce the reflected light.
When the inside rear view mirror surface changes, the outside
rear view mirror surfaces will also become darker.
When the ignition key is inserted and turned on, the inside rear
view mirror always turns on in the AUTO mode.
When the outside air temperature is low, it may take a little
longer for the mirror to darken in response to the detection of
headlights.
262
CAUTION
Do not adjust the mirror while the vehicle is moving.
Doing so may cause the driver to mishandle the vehicle
and an accident may occur resulting in death or serious
injuries.