Toyota Yaris Owner's Manual page 286

286
6-1. Using the air conditioning system and defogger
WARNING

To prevent the windshield from fogging up
Do not set the air outlet selector dial to
extremely humid weather. The difference between the temperature of the
outside air and that of the windshield can cause the outer surface of the
windshield to fog up, blocking your vision.

When the outside rear view mirror defoggers (if equipped) are on
Do not touch the outside surface of the rear view mirrors, as they can
become very hot and burn you.
NOTICE

To prevent battery discharge
Do not leave the air conditioning system on longer than necessary when the
engine is stopped.
during cool air operation in