Doh!! Sometimes I amaze myself - in a NOT so good way!! :-(
The compressor wasn't even turning......

But at least we now need to check the speed sensor, but....
Where the heck is THAT??
I've traced the brown and yellow/green wire back into the electrical "guts" of the corner of the engine bay, but don't know what I'm looking for there, and lose track of those two wires into THAT maze....

Regardless, I figured I could short the brown to ground and the yellow/green to a 12v source, and I'll hear the clutch "clicking" like it WANTS to engage, but not much engaged movement. Also, while the car is off, I can turn the compressor by hand, for what that's worth. The compressor seems to spin relatively freely (I expected decent resistance), just that the electro-magnetic clutch doesn't seem to really try to "engage" with authority.
So, bad clutch, or bad clutch/compressor unit, or???

Thanks,

__________________
Barry