It might just be your climate control unit. See if someone will let you borrow one, and then try that unit. Or jam the buttons really hard on your climate control unit. Those units go wacko over the years and are the main culprits for a "brokec" AC. I have to jam my buttons really hard in order to operate my AC.
1987 mercedes 300E
1995 e320 conversion(hated the 300e grill)
Monochromatic Paint (Custom Blue)
Flat Badged (front)
custom "carbon fiber" console
18 inch HP EVO rims
Sold! Now I drive a Monte Carlo SS