I just bought a 1995 e300. The ac worked fine when I got it, then it started to only work off and on. Now it is blowing heated air, not just hot air, heated air. My husband is a great mechanic, but has no experiece with mb's. Where should we start to find the problem. I love the car, but I live in the hot south! So ac is a must! If you can give us a clue where to start we would be so appreciative.