what this guy said. ^^^^
the blend doors may be bad, (unrelated to the air flow) try the ac and watch them turn from hot to cold. via the post for the replacement.
we have a member here who also had it stuck on defrost and foot, the arm off the vac pump where it enters the hvac box broke. it was the d/s that was broke. if you take off all the stuff the thread tells you to you can move this arm and linkage, you'll know if its broke off or not.
moving this if its still hooked up and not broke, it should move the air flow. you may need to pull the vac line off the vac pump, the round part in the diagram.
