TOYOTA 2010 Prius - Manual (Page 390)

366
3-4. Using the interior lights
■
To prevent 12 volt battery discharge
If the interior lights and personal lights on when the door is not fully closed or
the interior light switch in door position, the lights will go off automatically
after 20 minutes.
■
Customization that can be configured at Toyota dealer
Setting (e.g. The time elapsed before lights turn off) can be changed.
(Customizable features
→P. 587)