As a kid we always had AMC cars, my Dad was a Rambler man, still is, guess I didn't fall far from the tree
I remember in 1973 my Dad bought a brand new Hornet Sportabout wagon, it was our first ever brand new car, and the first one with air conditioning we had ever had.
I remember as a kid seeing the AC buttons and seeing the "desert only" setting
Living in the south east I had never been to a desert, but I sure wanted to go to one just so we could finally use that setting!
LOL,, my 68 AMX , has that setting on the AC selector also. I figured it just recurculated the air without and outside air comeing in when the AC is on. Also saw a listing for a 3 core radiator for it stateing desert air replacement.