I have been helping a friend write her life stories. In the 1930's her farm family had a Modal A Ford. (So did my dad.) Do you know they did not have heat in those cars? That's right. In the winter here in Michigan, people bundled up in coats and hats and put the old horse hair blankets, that had been used in their buggy and slay, around their legs. Here in Michigan, the winter weather made it difficult for the horse to pull the buggy so a slay was used. When the windshield of the Modal A got frozen, my friend's dad stopped the car and got out the bag of salt that was kept under the seat. He rubbed some of the salt over the windshield and soon it was cleared enough for them to be on their way.
In the 1940's my mother and aunt drove across the desert from Arizona to California. I don't know what kind of car they had but it doesn't matter since none of the cars had air conditioning. They bought a block of ice and put it in a pan on the floor of the front seat. Then they shut the windows and blew air across the ice. Walla! They had AC. By the way I was in the back seat.