Apparently this is a common issue on these cars as age catches up to them. Mine started blowing cold through the defrost vent only. Cycling the switch was no help. I did a quick isual inspection under the dash, and what little I could see didn't really show any apparent issues. In consulting the all knowing You Tube, it became apparent I was looking in the wrong place. After a quick clean up of the vacuum hoses underhood, it became very apparent the a hard plastic vacuum line had serious cracks in it. I put my finger over the cracks while the car was running and the AC began to blow out of the proper vents. I later taped them up with electrical tape as a temporary fix, and I'll cut it later and add a section of soft vacuum line or fuel line for a more permanent fix.