aircon compressor not engageing VT

[Galixia]

so did an engine swap and just putting the aircon back in. everything is hooked back up and gassed up and everything works fine except the compressor clutch wont engage for the aircon to work. checked the relay and found there was no signal coming from the pcm so tested the wire between the pcm and relay and thats fine. hooked up a tech tool and can manually engage the compressor and the aircon works, so the signal between the bcm and pcm then to the relay is all fine. it just wont do it when i push the a/c button on the dash. the car did receive a tune by power torque after the engine swap before there was any aircon parts put back in. any ideas?

[RiCeY]

Pressure sensor on the condensor plugged in?