Ac wiring help ls swapped 89 gmc 1500

So I swapped a 5.3 into my 89 gmc got it all wired up and tuned and running and finally had some funds to work on getting the ac going again.

I am using a 98 chevy condenser, 89 gmc accumulater, sanden 508 compressor, still have all the stock 89 gmc wiring in place.

Made custom lines got it all hooked up and charged so now I'm ready for some refrigerated air.

How do I wire this thing? Is it as simple as cutting the 89 green wire and splicing it to the single red wire on the new compressor?

I think I read somewhere about running the ac request through the pcm but I didn't replace my 89 pressure switch with a 01 style so I'm not sure if that will work. And i dont have 80 bucks to evacuate and recharge the system unkess i absolutely have to. Any help is appreciated, if you want or need specific pictures to help just let me know and I'll get themail for you.