There is a low pressure cutout switch that will keep the clutch from engaging. Most refrigeration compressors are not designed to run under prolonged vacuum conditions, they are cooled by refrigerant flow.

Do you just want to make sure it isn't seized? There isn't much else you can learn by forcing it on without refrigerant in the system, as it doesn't have anything to pump.

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1993 300D 2.5L Turbo