1983 300SD Climate Control Problems

I have a 1983 Mercedes-Benz 300Sd. A couple of days ago when i unlocked my car the vacum locks worked. Then when i opened them one day i heard a hissing nose like a leak from one of the door. SO when im driving along i hear a loud bang, right away i thought it was my vacum hose. WHen i got home and locked the doors they didnt lock with the pump like they should. That i really dont mind. Then a few days later my climate control (heater/air conditioner) stopped working. It doesnt do anything when i push the buttons its just sits there. It worked fine even after the doors stopped locking. I turned it on at night and the next morning it didnt work. I can feel warm air entering the cabin of the car. Im thinking it might have a vacum leak or some thing. I need help fast becuase it gets hot in the car after a while. Please any feed back welcome...