okay, so I have no idea about air conditioning or how it works, and I dont know any of the technical terms, so I'll do my best with pictures. So in the hallway is where the air is flows in: I open the grill, and I took out the air filter: http://img164.imageshack.us/my.php?image=img00197qf4.jpg notice the big hole. there is also a 'smaller hole' on the bottom(see the small hole and notice that it is closed). http://img389.imageshack.us/my.php?image=img00196th1.jpg closer view of the 'small hole' http://img389.imageshack.us/my.php?image=img00194bh9.jpg from what I gathered. When the A/C is turned on, or when our air cycler activates, the small hole starts to open up. It open up halfway(I imagine to let air in). It opens up halfway(maybe less) and then closes quickly, making a fairly loud popping/thumping sound. why is it doing that all of a sudden? whats wrong? what do I do to fix it?