I know I have probably worn this issue out, but still have not figured out what my problem is on my wife's 89 300se air conditioning. The ac has been charged and when working is extremely cold. But, one day it will blow cold from all vents and maybe the next time she gets in to go somewhere, it is just ambient through all vents. I have had a person or two say that it very easily could be the control button panel needing to be resoldered. I am not real handy resoldering things. Is it possible that a relay of some sort is not working correctly? I have checked fuses and there ok. I can't really tell if the compressor is kicking on or not. I did at one point have it recharged and the mechanic stated that the compressor was in good shape. Can anyone advise me on what steps I can go through to maybe track down my problem? I am very novice on test meters. I have also checked the mono valve and it checked out ok. Any clues you can give me would be greatly appreciated. Again, one day the air may work great all day long and the next 5 days it may just blow ambient air. If you move the dial to heat, it gets hotter than the hinges.