So my GM computer doesn't touch the AC system. The same wires that ran the AC clutch on the Toyota engine run the clutch on the GM engine. And that's the extent of it. The stock Toyota climate control system monitors the engine temperature and will turn off AC if it gets to high. I think it will also turn off AC at WOT. But I didn't attempt to translate those inputs from the GM engine to the Toyota CC system, so driver needs to turn it off as required. The GM computer would do similar, but I haven't explored integrating them, and probably won't. Doesn't meet my pain threshold yet. The only thing that's been a minor problem is that the GM computer can't bump the throttle when the compressor turns on, so on rare occasion the engine will stall if it comes on at idle. I might look into that sometime.
As far as the electric fan control. IIRC, the GM computer provides ground signals to trigger the fan relays. There's a pressure switch on the high side AC line near the DS headlight I think. It has two wires on it: +12v in and 12V out at very high pressure to tell the CC system to turn the AC off because its not getting cooled enough. But the switch has a 3rd unwired port that indicates a lower pressure level which tells you that you need additional air flow. You can get a lead for it at your local dealer and insert it. That will provide a + signal for pressure on that line, which you can convert to ground with another relay (you'll get good at wiring relays by the time you're done with this). Then connect that as an alternate path to ground for one of the fans so it comes on when AC pressure comes up. It's the same pressure switch that the aux fan guys use and there are some good write-ups on it.
Only problem is that that alternate ground confuses the GM computer and it sets a CEL about a bad fan circuit. Haven't figured out how to fix it yet ... probably another relay