fan controller question

Resurrecting this to get an AC wiring answer. Thanks to Goldduster318 and 72blunblu, I'm installing the Countour fan setup with the PAC 2750 controller. Goldduster318's schematic shows the AC pin on the controller going to the AC clutch cycle switch. Where do you tie in? Do you splice into the wire under the hood that goes to the compressor? Or is it somewhere under the dash. Any help is much appreciated.