Sometimes when I first turn on the air/AC, I'll hear a soft whirring or grinding sound that seems to be coming from the air vents. If I turn off the air and then turn it back on, the sound goes away. It doesn't happen often; I only remember noticing it a handful of times. Has anyone heard this sound before, or do you know what causes it? I'm wondering if it's normal or something that needs to be fixed.
The Prius uses electric motors to position the baffles in the A/C system. I suspect this is what you hear. Tom
pctra, At least in the Gen II, the soft whirring and door closing sounds on start up of the air conditioning -- meaning either heating or cooling -- comes from the servo motors setting baffles in the ductwork to direct air as as desired. I hear it when I change output location, say from defrost to feet & face. I would say that unless the sounds are very loud, or sound particularly strained, there is litttle to worry about. I suspect that the Gen III is pretty much the same. One caveat: If you live in a rural/suburban area, be mindful that mice and chipmunks have a particular fondness for setting up houskeeping in a Prius' ductwork. So a loud or strained sound could mean a stuck baffle due nesting, etc. But just in case, let's wait and see if a Gen III-er chimes in. Hope this helps.
