Airconditioner Vents on 2001 Nissan Pathfinder

Blower seems to be working fine. It will blow cold air out of the defrost vents and floor vents, but when I try to route the air to only come out of front vents I get nothing. All air seems to then be trapped and forced back out the floor and top vents.

Asked by for the 2001 Nissan Pathfinder