James Dorough

Good afternoon everyone.
I am putting together my 98 Trans Am Turbo Build and decided to run a Holley Terminator X instead of the factory computer since I know the 98 computer is pretty much garbage for doing what I am working on.
So when I got the car the underhood wiring harness had been removed, along with the computer, but I do have the entire harness and ECU which I know I will not need to run the engine since I am using the Terminator X, however I do not know what I will need from the harness in order to make the AC work.
I recently installed the main power feed harness "the cable that goes from the battery over to the main fuse block under the hood" and this powered up all of the accessories inside the car, along with the lights and the blower motor, but I do not know what I need to actually send the signal to the compressor to turn it on and off. Will I have to run the stock ECU in some aspect in order to make some of the functions work?
This is my first jaunt into the LS world, but I have built many classic mustangs so I am no stranger to general automotive work.

Thanks,
Mike