2006 Passat 2.0 air circulation system clicking
 

My 2006 Passat 2.0 has developed some click sounds in the air circulation system down by the front passengers feet. When you turn the car on, every once in a while after that, and I can force it when I hit the recirculate button.

Here is the sound:

http://www.shire.net/Memo.m4a

The first sound is when I push the recirculate button on and the second when I push it again. When you first start the car up you get both sounds one after the other and occasionally you get one of the sounds when driving. Always lasting a few seconds.

Separately you get a much slower clicking sound, more like a horse slowly trotting, when power is on in the car (driving or just sitting there with the key in).

Any idea what this is?

Thanks!
Chad