The compress is a variable compress and the clutch is energized all the time unless you depress A/C button on panel to off.
The auxiliary fan should not come on until the high pressure side gets to about 150PSI.
Also static reading (engine off) on low side might read 70-90PSI and will drop down to 30-40PSI after engine start with AC on(compressor energized).
Compressor will shut down if you get too low of a PSI on low side or a out of range on high side.
If you have gauges you could jumper 12 volts into the single wire on compressor to energize clutch and look at the low/high pressure readings.