Manual

My daughters and I have recently purchased a 1973 Mercedes SL. Very cute but very hot. We can't turn off the heat! We know something is stuck on. We are looking for a manual that would describe how to at least disconnect the heater for now. We have been to the library and came across the MB manual but it only discusses engines. I have researched EBAY and see several manuals but gosh, what type of manual will cover everything? I bid on a Haynes manual but now that I saw the library manual I am thinking that it too will not cover the issues we need addressed. Besides the heater the interior dash lights don't work. There are other items that are all non-engine related. Any help would be most appreciated. Thank you

Take it to a service center. They know all, haha. dunno, ill ask around work and see if i can find anything out. peace.

Engine compartment on the drivers side next to the brake master cylinder. You'll see an air actuated bellows on the firewall that goes left and right. The rubber is probably leaking. Push it left or right to control the heat.