What sort of problems? Smell - covered in lots of previous posts. Leaking evaporator unit? There was a very excellent post a while ago about changing out the in cab evaporator unit (could be wrong about the terminology). The member posted a lot of information with pictures. I wouldn't want to tackle that job, but I would feel confident that I could, armed with that kind of information. There was even a discussion about how to keep all of the debris out of the vent system to make the AC evaporator last longer.