How to use my 77 climate controls?
 

Hello all, I bought my 77 450SL a few months ago and am going to need to use my AC soon here in Phoenix. I don;t have an owners manual and for the life of me can't figure out how to use the climate controls. It has one knob marhed "fan", one knob marked "AC", and 2 slide switches. I get the fan and the AC part but I don't get the slide switches. They have Max, Right temp, left temp, down, defrost lines pointing right and left and off marked at places I can;t figure out which knob to use to do what. I looked for a manual but everyone is backordered or wants a hundred bucks for one and all I want to do is operate my heat and AC. Can some kind soul clue me in? Thanks in advance, Billybuck