AC compressor clutch not rotating

[RGMTx5]

Quick brief:
The AC on my E53 is no longer cold. Toward the end of last summer it seemed to be slow to catch on (10 minutes plus high speed), but as of this summer it's simply not blowing cold at all, no matter how long the vehicle is running. Figured it was just low on r-134 but when I read the low side pressure it was at a whopping 80psi.

After finding that surprise, I figured a more thorough eval was in check. Well it didn't take long for me to notice the compressor clutch was not engaging - nor the aux fan.

I'll be checking for 12v to the compressor this evening, but still - since the AC slowly faded into submission I'm wondering what simple checks I'm missing. Would the low pressure switch being thrown lead to such high psi readings? I also discovered the AUC sensor (64116917001) was broken on the AUX fan (new one on order) - but still, the AC not blowing cold air is a different beast altogether.

Thoughts? Links?

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2005 BMW x5 (E53) 3.0i