[Alan Anderson]

False on a DIO means the signal is being pulled low. A properly wired pressure switch will do that when the pressure is too low and it is calling for the compressor to run.

What do you see the indicator doing when you completely disconnect the pressure switch? If it still says the switch state is false, there's something very wrong. Either the hardware (or the cRIO image) is faulty, or your code isn't reading the input properly.