so i have a 5.9 durango and a few months ago there was a rodents nest in the blower but it blew it out and im pretty sure its good cause i blew a 150 psi air compressor through the passages but i dont have anything coming out of the dash only defrost and it is 134a

 

Blend doors.

 

Or vacuum leak..... the vents are all vacuum powered, and if there isn't any vacuum, then the default it the defroster vents.