If your 95 is anything like the earlier models, there's a low pressure switch attached to the AC drier by the left headlight. The low pressure switch has two spade contacts directly on it as opposed to the high pressure switch with two connectors on pigtails. Disconnect either wire at the low pressure switch and see if the compressor disengages. If so, there is a rogue signal from the PBU. If not, there's a problem with the compressor controller.

Which begs the question - has it always been this way? Did you have the AC system serviced before this happened?

Sixto
87 300D