This happened to mine after a friend got in the car and tried to close the center vents. After they popped in the first time they never stayed in again for long. The center vents have a limiter that only allows them to rotate up or down about 45 degrees (or at least my 2006 does). If you force the vents more than that, it bows out the plastic and they fall in to the duct. The outer vents don't seem to have this limiter and are allowed to rotate fully closed.platinumdetailing said:thanks a lot I guess I happens often.