my AC (87 190e) went bust a couple of weeks ago - while driving on the freeway, it started blowing hot air. After switching off and restarted, it engaged for a couple of seconds, then made a rattling sound and disengaged. I didn't try again. Then last week it didn't engage at all - now its totally dead, just blows regular/hot air. How can I check to see if the compressor is OK, or its seized up? My guy quoted me over a 1000 buckes for a new compressor and the works. Want to make sure the compressor is the problem before I sink in the money.