VY LS1 A/C Wiring Help Needed

[evilstuie]

Hey All,

I have the majority of a VY commodore engine and body harness installed in a custom setup, using the BCM, PCM and harnesses.

I've just completed setting up the A/C system with a universal EVAP unit which uses a 12v switch for the fan which I need to wire in to tell the rest of the car to activate the A/C clutch and tell the PCM the a/c is on.

I've looked at the wiring diagrams and pinouts for the PCM and have come to the conclusion that the 2 pin plug going to the A/C clutch is actually meant to have another 12 volt source going to it to power the clutch, and the wire going back to the PCM is just to let it know the clutch/ac is active.

The clutch will draw a chunk of power to engage so I can only assume there's another plug or something missing that should connect to that wire for the power supply to the clutch.

Can anyone help out with where this power comes from?

 

[evilstuie]

I think the power is supplied by the relay back into the cabin via that green wire, I can test this tomorrow, so I guess the bigger question is the wiring behind the stock EVAP switch.
When you turn the fan on or press the AC button does this ground something in the BCM, which then sends the ground to activate the A/C clutch relay, then this powers the green wire on the engine/body connectors?

And if this is the case, which wire on the BCM is doing this?