as above, check fuses.....[also there are three relays, front rear fans + compressor]..... you can hear individual fans, front and rear turn on with a/c switch, there should be a change in RPM when you turn on A/C compressor. Manual says to try jump compressor directly as mentioned above. I believe my compressor is dead, need to find out from Glen if this is the same compressor or different compressor after my engine change. My a/c worked just fine before my engine change........

at current, my fans work but compressor does not engage/turn on.
Unfortunately for me, I am a couple weeks away from having time to looky loo!
good luck and let me know the outcome!