If I missed it it, I apologize. But what compressor are you running? The factory compressor is controlled by the ecm not just at the clutch but it varies the pitch on the vanes right? I didn't think that variable compressor is compatible with the VA unit?
If you are running a sanden compressor then why not leave the ecm out of the equation for the ac? You could run a 5 volt ref to one side of the trinary and from there to the ecm to tell it that ac is on. It would only make when the specified pressure is reached and you could set it to run at, say 40% on the pwm when the AC calls for it.
It really doesn't take that much fan to cool off the condenser. When we charge systems here, the fan only cycles for 8-10 seconds at a time and doesn't cycle again for at least another 90 seconds. You can watch the high side pressure drop quickly, you would swear it had a leak. So in my mind it would be simpler to do it that way and not have to worry about the oem pressure sensor.
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Donny
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