I've got a 2007 Ford Focus SE that I bought about eight months ago. In the fall, I noticed that my windows were fogging up more than usual, and tended to be complimented with a musty odor. Sometimes when my windows fog up, turning the fan up sometimes makes the problem worse, to the point where I have to roll down the windows with the fan on high blast, which is not fun in the winter!
Also, when I've got my front vents (face, whatever they're called) turned on, the musty smell comes back, and if I try to turn on my air recirculation button, nothing happens. If my windows are rolled up, there are absolutely no outside smells entering the vents.
What does the problem sound like, and what could I do to fix it?