[sparkydp]

It sounds like you might be setting the relay in more than one place. I would remove all but one of your sets, see if that helps (do a find all instances on the relay set vi). Make sure you aren't trying to control the same relay with the joystick, that you've setup somewhere else to be your compressor.

If not, try setting the relay directly, with a constant value (instead of wiring to the joystick), and see if that value fluctuates rapidly too.

If that cleans it up, start debugging the joystick output.

Make sure you're checking the error out on your set, and that you aren't getting any error messages in the dashboard.