AC problems, periodic "chirp"

Hi guys,

Here is the deal. AC is running cold and the resistor was recently replaced, so I'm working on all four heat/air settings just fine. The air is weak (I know, I know, Cabin Filter). So, I'm having the Cabin Filter changed next week. Other than that, I'm in good chape, accept for a periodic chirp.

I hear an occasional chirp from, what seems like, behind the glove box. The chirp is very short, only slightly audible, and seems to happen without uniform frequency. I have decided that it is related to heating and air because sometimes the chirp will happen when I've come to a complete stop, and it also only occurs when the AC is on. I would say that it happens about 4-5 times a day, now.

It kind of sounds like a belt, but I don't know if there is a belt near the glove box. Perhaps it is because I need the new Cabin filter. I'm just looking for ideas. Thanks, gang!

Bird stuck in cabin filter area? Sorry, couldn't resist. Change that filter and see if it still chirps.