Hi -

Have 2002 Regal LS, and periodically - and lately a couple of times a week - the heating/AC system will emit either a high-pitched whistling sound, or sometimes a lower-pitched honking noise. The noise is definitely coming from within the dash, i.e., not under the hood. If I fiddle with the system - turning it off and on and adjusting the fan speeds and air direction settings, it will eventually stop...but it is damned annoying; sometimes takes five minutes or more to get it to shut up.

It sounds like air being forced through something - maybe a flap not closing properly or something like that.

Anyone have any experience with this?

thanks!

 

The first thing that came to my mind is paper or something down by the fan. The other idea is the bearing in the fan could be causing a whistle sound. It isn't to tough to get the fan out and check. At least it wasn't in my 92 buick when the fan just quit a week ago. I haven't had my head under the dash of of one as new as yours though. Another thought is the direction of the air whether floor heat or vent etc. is controlled by vacuum, I wonder if you have a vacuum leak on one of the plungers that pulls or pushes the gates? The best way to tell is to listen when you change from one setting to another. I hope these Ideas help KM