Air vent making loud noise

[musicmanmu]

Hey folks,
As I'm sure most of you are experiencing, it's darn cold in many parts of the east. -4 this morning. Anyway, driving to work today, I had my heater on about halfpower, and about 30 min. into my commute, the air vent began making a bubbling, chirping sort of noise. I turned it off until I got to work. When I parked, I turned it back on, and it was making a very loud, straining noise.

Anyone know what could be wrong? Thanks!

[Rayven01]

I'm not sure if it's exactly the same in an '09 but check for a drain like this by the blower in the passenger footwell: viewtopic.php?t=8709#p411624" onclick="window.open(this.href);return false;
Sounds like it may be plugged (frozen maybe?) and backing up into the blower.