The AC/heater on my Mazda Tribute only blow air.

The ac/heater on my mazda tribute only blow air when is on the highest setting. It just started doing this about a month ago before that I noticed that whenever I turned the ac or heater onn it would make kind of a squiki sound like a ballon when is letitng air out then all of a sudden it quit making that sound but nowit only blows air when I have it on the highest setting. I also notice that it when I turn the egine onn it leakes water not inside the car but outside towards the passnger side. Can this be someting serious or just a simply fix?