The selector for the heat / defrost will not direct heat to my defroster ...help

I had same problem. Mitsubishi made stupid small little plastic pieces fit the vents at the top of the dash for 2002-2003 year which actually slip out and fall down into the craves below and obstruct the vent control!!!! MitsubishiSuxX! You can try a long sender tube and a vacuum suction to see if it can be dislodged, or a metal coat hanger.....and a bore camera to see it. Good luck...don't great to post back:))