Compressor wont run at all

[Mark McLeod]

The Open Compressor specifies the same DIO used for the pressure sensor.
PWM black wire to the outside of the Digital Sidecar?

Open Compressor specifies the same Relay you have the Spike connected to? Black wire on the PWM out of course.

It doesn't matter which pressure sensor terminal gets connected to black or white PWM wire.

You can also test the compressor using a limit switch in place of the pressure sensor.
The Relay indicator LEDs on the Digital Sidecar should light green when the compressor is supposed to be on.

The Driver Station is enabled I assume.