Why does the air conditioning blow out the defrost only in my 98 dodge ram 1500.?

[Robert]

It doesn't matter where I put the control the only place it blows is out the defrost

 

[The Eagle Keeper]

The a/c control system has a vacuum leak & it won't move the vents. Those are a pain to get to.

 

[pulntubz4ever]

vacuum leak that supplies the inside is leaking or broken