A/c compressor not engageing

[Chuck Pierce]

Ok.... pulled the plug off the MFTS( I had other MTFS symptoms low boost
and engine over heating symbol, Fixed those ), the a/c clutch still does
not engage the compressor( this is with a/c set on AUTO and temp set to
LO ). The low speed radiator fan does comes on. The a/c sort of worked
when I got the car in August, but since the blower fan was not working
consistently it would turn its self off when the condenser iced up or it
decided there was not enough air going across the evaporating coil..
Where to go from here?  Ideas or wisdom  appreciated

Chuck
91 20v Avant very slowly getting sorted out