Why the AC compressor turns off on lower fan speeds on 1990 Nissan 300ZX

The AC Compressor only comes on when the controls are on high. Tried 3 different resistors still same result. I even replaced the controls nothings changed, it only works on high.

Asked by for the 1990 Nissan 300ZX
The freon level may be low causing the evaporator to freeze at low fan speeds. Have the A/C pressures checked.