Hi all. The a/c on my '87 300E stopped working a few weeks ago. Not working at all, nada, after working great. I am a reasonably competent backyard mechanic (have changed shocks, springs, fluids, plugs/wires, but nothing major) but have never done any a/c troubleshooting of any kind. I'm not even sure how to tell if the compressor clutch is engaging. Can someone give me some pointers so I can try to narrow the problem - I want to have an idea of what is going on so I don't get ripped off by a shop doing any unnecessary work, even if I can't fix it myself. Thanks.