Replaced the original leaky servo with an aluminum body servo about 3 years ago, replaced the push button climate control, replaced the burned out amplifier and replaced the aux water pump around the same time AND got no heat. The defrost push button was the only thing that would work and it would blow heat to the front windshield. Puzzled through most of the year and frustrated I decided to once again tackle the Sir Vo. Removed my glove compartment today and started once again to follow every vacuum line and check valve and boy was I surprised to see an open four way connector. I started to diesel up, placed my thumb on the open connector and then quickly began to push all the climate control buttons. Got all the vents to finally blow air. Now I need help on what to do next to get cold air. Previous owner removed the belt from the compressor which leads me to believe that it seized along time ago. If all I need to do now is replace the compressor and replace a few other parts then I will end my search for a 1987 300sdl(casting number#17). I really enjoy my 300 SD. I purchased the car from a Dutchman who drove it 134,000 miles before selling it to me. Every service record was handed to me including the filled out mercedes booklet. The servo has been a nightmare and now with a growing family I need to either quickly get AC or quickly get rid of it. Mechanically the car is a work horse, pampered I might add by my strict oil changes, valve adjustments and you name it. I lack expertise in Air Conditioning and I'm asking one last time for help. I don't mind taking the car in but I want to make sure that its worked on by the right people. What steps do I follow and what are the other parts that need to be checked? What are all the parts in a W116 300 SD that make the AC system work? I am familiar with the common parts like expansion valves, compressor, condensers but thats about it. I want to keep the car but here in Southern California it can get kind of hot.