No success, yet, but in prying, pulling, tugging, etc., I've finally seen the thingy that sticks up into the middle vent. It appears as a metal pointed prong or arrow head, in about 3" behind the louvers. It is very difficult to see inside the A/C vent behind the louvers. I don't know yet what kind of tool to use to press it downward to pop it out, but will try today starting with screw drivers and the like. Boy, have I butchered this thing - wonder what a replacement is going to cost me??? Removing the radio has not helped one bit because of the existing metal box surrounding the radio that keeps one from accessing the A/C unit.