97 Voyager selector vent position

I have a 97 Voyager that only blows air only from the dash vents no matter what position the selector switch in turned to. I have checked for vacum leaks , found and fixed one with no improvement . From some other postings it appears that the default for the vent position to go to if there is a loss of vacum is the floor vents. I will be needing the defrost mode soon. Any input would be appriciated. Thanks