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