For those who don't know the different model numbers, more info on brand, year and model will help as we can then look at drawings to see where the power goes and how it might be connected. Your guess that one leg is missing might sound right but with the complete info we can look at the drawings and options to see. Also when you say the Air cond. has stopped cooling, what do you mean? Does the blower run but not cool or just the blower never starts?