Does anyone have any idea about this whistling sound? (I do know that I'm a little low on Freon and need to top off the system.)

 

Sounds just like what mine is doing since I did a thorough cleaning of the vents in my '98 last weekend. In my case it is the foam gasket around the shut-off doors behind the grill being gone. They were rotted to nothing and blew out in little pieces. So now when one of the vents are shut they whistle just like that as the air gets by. Open them up and it stops. That's my guess, some of your gaskets have failed and gone missing.

 

You can laugh if you want but the whistling sound was coming from a vent that was partially closed.

I opened it and the sound went away but would return once I went to close of the vent. I took off the center panel, cleaned up the sticky felt grommets and it went away for good.

Just thought I'd share. Thanks for the response far-trader.

 

You're welcome Sxynerd. And no laughing here, when mine started whining like that I was annoyed until I tracked down the cause. Luckily I stumbled on a fix (open the vents, for now anyway) after only a couple minutes. Glad to hear you got yours sorted.