[RyanN]

Does the green LED next to the relay ports on the DSC light up when you enable the robot? Since your compressor relay is on port 1, the port 1 green LED should light up.

If it is on, try reseating the PWM cable into the Spike. I was helping Team Combustion last year and they couldn't get the Spike to work. This was ultimately the problem, as the cable can seem plugged in, but actually misses the female socket inside of the Spike.

If it is off, check your code (post it if you would like with screenshots), and check the wiring of your pressure switch.

Since you're overrriding the pressure sensor right now, my guess is the cable isn't seated properly.

Please answer the first question though. That will help us all out trying to figure out your issue.