HVAC controls are operated by vacuum. the default (no vacuum applied) is to go to the defrost vents.. Most commonly, the vacuum hoses come off the connector located "behind" the radio.. remove the radio and look behind that area.. you can also look from thr passenger side of the vehicle, behind the center console/hvac area, for some of the view.
Plastic or rubber hoses, usually plastic, and colored (red/green/blue, etc)
FWIW:
This can be found under search.. I have seen it personally.
Ray
