Ok, so I have a 2007 with about 43000 miles. Just out of warranty, I started noticing an on and off semi high pitched sound coming from what I thought was the far right dash vent by the passenger door when the fan was on the lower two settings.

It slowly became more frequent and is now constantly annoying me. I can't pinpoint the sound though. It might be coming from directly behind the A/C & radio or somewhere in the 2 passenger side dash vents, but I'm not sure. If I turn the fan up to the 3rd or the highest setting, the chirp goes away completely. It also doesn't come back for a few seconds or up to a minute or so after turning back down to 1st or 2nd setting.

Any ideas where to start?

 

Sounds like time for a blower motor replacement or there is somthing stuck in the blower motor cage either way you have to remove the blower motor.

 

Mine is starting to do that also, it sounds like a bearing.
It doesn't do it all the time though, on low speed only.
It goes away if I turn the fan up to a higher setting.

I'm just ignoring it for now, or turning up the radio.

To OP -I used to live in McKinney ('92-'94), things have changed out that way.

 

Replace the blower motor. I had this type of noise happen on the 06, and the day of my appt to take it to the dealer the fan failed completely. Unless you want to drive around with no heating/cooling, I would get it taken care of sooner rather than later.

 

Its the blower motor I just replaced mine and the noise is gone....