Supporting A/C control is possible, and as it differs slightly across various cars we dont claim to support it out of the box, but its been possible on a few cars.
We can control the compressor on using a Misc Out channel, we just need to work out the function of the inputs.
With the Nissan I have two inputs - one is the Throttle pedal (which cuts the compressor on WOT) and the other is the A/C on button.
So we need to make a truth table up like this:
Pressure Switch | Compressor On | AC control |
Off | Off | Off |
Off | On | Off |
On | Off | Off |
On | On | On |
And with a table like this all we'd need is an extra relay