My brother has a 2000 maxima. The a/c was working fine up till a few weeks ago, when it started to blow warm air, that lasted a day, then went to back working normally. A few days ago went back to warm air, and has been like that. He just moved and doesnt know a reputed repair shop (oxymoron?). Anyway before they tell them the compressor needs to be changed, does this sound like coolant probs. or is the compressor the obv prob?