General A/C questions - missing some components

You CAN run without it. Depending on year, model, etc, you have several switches all in series to run the clutch. This is not necessarily specific to your car

1--the main dash control, obviously selects heat/ cool, and turns on that switch for clutch, if all others are "made."

2--temp control cycles clutch on temp

3--"freeze" control on evap if temp at evap gets too low, drops out clutch and allows airflow to defrost evap

4--low pressure control drops out clutch on loss of system pressure.

The simple "hang on" A/C I used to have in my RR was very simple --just a blower switch and temp control on the evap.