Toyota Prius 2010 Repair Manual page 369

Inlet and outlet modes will remain unchanged when the solar ventilation switch is turned on after the power
switch is turned off.
(c) Stop Control
(1) When the solar ventilation switch is turned off or the power switch is turned on (IG), the solar ventilation
system will stop operating.
HINT:
After the power switch is turned on (IG), both the inlets and outlets return to the mode that they were in before
the power switch was turned off.
2010 Toyota Prius Repair Manual