1995 4.9 Sedan Diville Won't blow hot air

Check the blend air door for operation.

There is either an access door in the glove box(used to primarily access the passenger airbag connector), or you need to remove the glove box. Behind that is a linkage rod for th blend door. Check that the rod is connected to the actuator arm, see if it moves when the system is commanded hot/cold. Disconnect the rod and manually move it, observe the change out the vents.