'91 240 a/c clutch won't engage

[kyswisher]

My '91 240 with retrofitted a/c hasn't blown cool air in years. I found that the a/c hose between the compressor and drier was worn through so I replaced that, filled with new refrigerant/oil, only to find that it still wouldn't work.

I ran the compressor clutch sire directly to the battery and the clutch engaged. I started the motor, re-attached the compressor wire to the battery and all i get is a grinding sound, presumably from between the clutch plates.

So I need to diagnose the reason why the interior switch won't work, and diagnose the non-functioning compressor.

Any thoughts/advice?