I can only get air to come out for defrost only on my 89 cherokee, there is nothing for any other vent, on any other setting, I assume there is a major blockage, somewhere........Has this happened to anyone before? or does anyone know where the block may be, I have no clue where to look, I assume its behind the dash somewhere.....
Any help would be greatly appreciated =)

by chance is there linkage that has fallen off behind the dash?

There is a vacuum line that runs into the cab from the engine compartment on the passenger side. It changes from vent to floor to defrost via a vacuum switch on the back of the controls. If you don't have the vacuum line hooked up to the engine it won't change or if you have a vacuum leak somewhere.

Thank you!:D

There is a vacuum line that runs into the cab from the engine compartment on the passenger side. It changes from vent to floor to defrost via a vacuum switch on the back of the controls. If you don't have the vacuum line hooked up to the engine it won't change or if you have a vacuum leak somewhere.
You should replace the above mentioned hose all the way back to the small plastic ball that's mounted behind the bumper, on the passenger-side. This ball is the vacuum reservoir for your heat/AC system.