After searching both sites I didn't find anyone with my specific problem. I have a 02 sedan. The ac has a low pitched squeal when on levels 2 or 3 but not 1 or 4. It sometimes goes away when moving but comes back when stopped with the brakes on. It does it when on ac or full ac with the circulation selected too. It sounds like it's coming from inside so I don't think it's the compressor or belt. Any thoughts?