I recented had my A/C recharged with R134. But i still have problems with the A/C blowing out the defroster vent. What would cause this?

Please advise.
Thanks,
Jason
:hail:

 

A/C out the defroster vents has nothing to do with the type of freon or if it's full or empty. When you switch it to heat will it come out on the floor? The defrost location is the 'default' location for the air to go. Could be:
No vacuum to the AC controls(bad line, unhooked line)
worn out a/c controls
flapper and/or vacuum pod in the dash isn't changing the air flow.