At some point yesterday my 2009 Prius starting making an odd sound. The sound is constant, whether idling or driving. It's mostly inaudible when the A/C is on, and is only audible from inside the car. I can't hear it at all when I pop the hood and listen outside. It almost sounds like fluid being shifted back and forth. There are no codes being thrown. I've tried to include a video of the sound. Any help would be appreciated!
If you can hear it louder by the kick panel on the right side of your footwell (where the gas pedal is at), then it'll most likely be the servo that controls the AC vent controls making that noise.
Try downloading and comparing the sound in the video attached to this post to the sound you are hearing. If it's similar, JC91006 has probably called it. There isn't one servo controlling the A/C flaps, there are three. Two are on the more-accessible side by the driver's footwell; put your head down there and look and you can probably see which one's acting up. The third is on the other side and no picnic to get access to, though you'd possibly be able to at least see it with the glove box removed (I've never tried). The ones that are easy to reach are easy to fix.