Loud Whirring/Low Airflow from Blower Motor

Hi all,

Our 2017 Prius decided to celebrate the expiry of its warranty by developing a whirring noise in the HVAC unit that gets louder when the fan is turned up. The dashboard vents are also blowing air only weakly regardless of how high the setting is.

The noise also coincides with a trip we took to the country, during which leaves were falling all over the car for several days, so I wondered at first whether it was possible that debris got into the blower motor somehow. I removed the panel under the glove compartment to take a look and encountered the big white casing so couldn't figure out how to inspect much closer. But I did notice that the noise either diminished or got louder if I pressed a piece of the black part that's on the bottom of the casing, if that provides any clue.

Here's a video I shot showing first the whirring noise with the fan set up high, then getting louder and softening as I push on the black part. Then I turned the fan all the way down and back up to get a real sense of the noise.

Before I go the dealership route, does anyone have any thoughts on what the issue is likeliest to be and whether or not it's something I could handle? Thanks very much!

 

I'm sure I have the terminology wrong, but from what I've read the gen 4 doesn't have the HVAC parts as accessible as previous generations. When you pop open the panel under the glove compartment mostly what you see is a white plastic casing.

The video I embedded above is taking forever to process on Google Drive so it hasn't been working for me, but here are a couple of pictures that show what I mean. The first one shows what's visible under the panel. The second one shows the piece of the black thing that I was applying pressure to dampen or increase the volume of the whirring sound.

 

Definitely at least a chance, where we were (i.e., not Ireland). Though the sound does seem to trace to that black piece above.

 

I tried to find specs/instructions and failed but admittedly it was a quick look. I'll have a more thorough read later.

 

Mystery solved, in case anyone ever has the same problem. When I went to replace the cabin filter, I discovered that it was all torn up (or, more likely, chewed up by a rodent of some kind). Then I pulled out the blower motor and found that the shredded felt had fallen inside. When the motor was on, the fan was whipping against the felt—the higher the fan was set, the louder the noise. Removed the felt, screwed the motor back into place, problem solved. Thanks for the advice, everyone.