[Nirvash]

Originally Posted by Arkamond

Then we wired the 3-pin PWM connector to Relay 1, making sure the black end is on the G on the Spike-relay and on the relay panel the black is on the outermost pin.
But the issue became that it didn't work. It only showed a reddish-yellow light, until we connected it to the Digital I/O board on slot 1. Then the light became completely red but the compressor started running.
-We get a red light no matter what (unless we switch positive and negative around) on our Spike-relay. We're not sure whether this is correct or not, but it is working in this fashion.

We wired our two wired pressure-release valve to relay 1, as we thought it would go there instead of the Spike-relay.
-But it didn't work, we got up to 135 PSI and it didn't work.
/Tl'dr

I'l happily answer any questions.

If I am reading this right, you have your Spike connected to DIO 1 and your pressure switch wired to Relay 1?
If that is so then it is backwards. The Spike should got to relay and switch to DIO.

Where did you place "Compr Control Loop" and "Compr Enabled" in your code?