I have a 2009 Chevy Impala LT that has 2 minor problems, more nerve racking then anything but figured maybe someone could offer some input. When I turn my AC off in my car I get a knocking sound coming from behind my glovebox, and the sound goes on for a good minute at least before stopping. Also I have automatic locks and when I lock my doors all of the locks don't always lock, usually it's one of the ones on the drivers side not doing it but sometimes it happens on the passengers side as well