Re: Buzzing sound when the AC is ON. I have heard it as well. It didn't bother me much, I knew it had to be the AC and besides these cars make so many oddball noises I just ignore them most of the time.
Re: Buzzing sound when the AC is ON. And they still want to 'bell the hybrid' with regards to the OP. Lots of people have heard the noise... http://priuschat.com/forums/gen-iii-2010-prius-main-forum/64630-air-conditioning-noise.html
Re: Buzzing sound when the AC is ON. It would appear to be normal. There are many other threads regarding this already posted. The noise is a buzz or hum which is loud at first and settles down. It's the electric a/c compressor.
Re: Buzzing sound when the AC is ON. Being a variable speed compressor, the more A/C demand, the higher pitched and louder the buzzing will sound as the compressor spins faster. Interesting note: While in ECO mode, the compressor will run at a slightly reduced speed to conserve energy.
To add on this: the kind of compressor used is different (it is a [ame="http://en.wikipedia.org/wiki/Scroll_compressor"]scroll compressor[/ame]) and is it of variable speed (speed, therefore noise, change according to cooling demand). Usually, car A/C's doesn't have either of these characteristics.
My 'mechanical airplane buzz' can be heard even while in the car, but mostly while it is stopped. I determined it to be related to the AC right away. However, when it finally does decide to die down, turning the AC off and back on usually causes the sound to come back. Also, it is present when the windshield defrost is on, whether or not the AC is on. I just use it as my alternate horn, i.e. a more pleasant way to warn pedestrians of my approach. I guess it saves me the cost of installing a bell. lol
My compressor, is also being replaced, under warranty by my dealer. It is important to note that I was involved in a >20 mph front end collision, which impacted the front passenger side of the bumper, etc. Immediately after the accident, they noise from the A/C was a lot louder than before. However, my body shop insisted that nothing was wrong with compressor. They brought it to a local Toyota dealership who concluded the same. After bringing to my dealer, they initially tried to say it was from collision, but when state farm asked them to prove it, as there was no damage to the compressor externally, they opted instead to replace it under warranty. I will get my car back tomorrow, and will try to post an update on this when I return from a raod trip next week.
So I'm bumping an old thread. I just noticed this same noise for the first time since owning the car. Have been running the AC all summer so far. What stands out to me is I never heard this noise before, mainly because the windows would be rolled up and I'm driving. However today I heard the noise inside the cabin with the windows rolled up and driving about 5-10 mph. Stopped the car and took this video. The ICE is running during this video yet the AC compressor is clearly louder. It's obviously the AC compressor because when I turn off the AC switch inside the cabin, the noise stops immediately. I know the consensus for this noise is normal but I would like for someone more knowledgeable about the Prius, than me, to chime in. (sorry, I'm so used to my 1998 Tacoma and old school technology).
That doesn't sound right to me. Does the A/C compressor have any outside moving parts? It could be that there is something lodged in there, like a twig or a piece or paper. I would do a thorough visual check and if I couldn't see anything wrong I'd take it to a repair shop. Maybe it's failing from the inside.
