As I was driving to lunch on this very sunny day, I accidentally pressed the front defog button. The air started coming out of the top vents, which is not what I wanted, so I pressed the head-feet button. NOTHING HAPPENED. The air didn't switch vents!! I heard the air start blowing harder when I switched the buttons, but it was still blowing onto the windshield. I recently installed a cd changer in my dash, so I'm thinking a connector got knocked loose or something, although I don't really know how likely that is given that everything clips in. Has anyone had this problem, or have any ideas what could be wrong? We're having a heat wave here, I need my A/C to blow right in my face!! This sucks!

Thanks in advance!