Defogger Defroster doesn't work on 2004 Chevrolet Impala

The heat and AC work from all vents except the defroster defogger main vent. The blower runs but nothing comes out of the main vent. Any repair suggestions?

Asked by for the 2004 Chevrolet Impala
Hi, sorry to see you didn't get an answer to your question, were you able to find out what was causing the problems with airflow to the main vent? Was it one of the motors for the vent flap?