Well the defrost actuator was sticking and not opening up all the way so I sprayed a silicon lube where the rod hooks onto the plastic piece that operates the defroster and it is working right now. Air is still comming from dash vents all the time.Not like its blowing out or anything but air still comes out of dash no matter what .And by the way thanks for your input.

 

Sounds similar to my issue, where is the defrost vent door located on the blazer? I have a 97. Thanks

 

defrost door is under dash to the rt. of stering colum

 

Thanks