I have a 2003 Supercrew Lariat, w/climate control when i change from defrost to floor setting, it never changes, the heat still comes out of the defrost vents, but when i go from def to vent, it works like it should. I have plenty of heat, just not where i would like it to go

any help would be appreciated

 

Sounds like you have a vacuum leak. Start checking vacuum lines and associated components.