Jim,
If I am not mistaken, I think the switch to the compressor clutch runs the system. The voltage input may pass through a relay first. The condenser fans will probably be fired up by a trinary pressure switch on the high side. Until the pressure, due to the compressor operation, raises the pressure high enough on the high side, the condenser fans will probably remain off. Some systems turn those fans on all the time, so this is not an exact input, given I do not know your specific system. I think 90lbs, low and high side pressure should be enough to not have a low pressure cut off sensor stop the compressor from coming on. There are two wires that go to the clutch. You need to measure there and see if you are getting voltage with the dash switch on. You could apply voltage with a temporary wire to see if the clutch and system is operational. That would confirm a wiring/switch/breaker or fuse issue that feeds the compressor clutch or the clutch itself.
I know that you indicated that you cannot see the clutch but in order to diagnose this problem I think you will need to gain access to the clutch wiring somehow.
Later Ed