hope the title isn't to confusing....when I adjust the airflow from defrost, feet, etc to the face/dashboard setting there is a loud clicking/clunking noise that comes from the dashboard area behind the radio. it eventually goes away if I leave it in that position and it goes away immediately if i switch to another air flow setting (defrost, feet, etc). I am assuming there is something going on with the system that controls the airflow dampers. any thoughts on what it is, where to look, etc??...Thanks