I finally got back to this and it does appear, if I'm doing it right, that the clutch gap is too large - around .9 mm when it's supposed to be .5 mm +- .15 mm. I now know my high/low pressure sensor is fine, my rpm sensors all hooked up, etc. So it looks like it's something at the compressor and/or clutch. I give the compressor 12 volts and nothing happens, nothing moves, nothing clicks, just silence. It's hard to believe the compressor is bad - when it would kick on it worked like a champ. But now is just won't kick on at all. There's an old Larry Bible post that narrows this down to "clutch coil is open" or "air gap is too wide". I'm guess I'm going to get the pin wrench and try to take off and adjust the spring plate. Any words of wisdom appreciated.