Lexus 2003 SC430 Owner's Manual page 171

AIR CONDITIONING
AUTOMATIC AIR CONDITIONING CONTROLS
"You can adjust the brightness of the display. See
"Instrument panel light control" on page 59 for details.
The display may be tinged in purple due to the reflection of
sunlight, but this is not a malfunction.
The automatic air conditioning automatically maintains
the set temperature.
21sk01
154
In the automatic operation mode, the air conditioning selects
the most suitable fan speed, air flow, air intake and on–off of
the air conditioning according to the temperature.
The ignition switch must be in the "ON" position.
NOTICE
To prevent the battery from being discharged, do not
leave the air conditioning on longer than necessary
when the engine is not running.