If you don't know this already, the AC comes on when you have the dial on DEFOG or DEFOG+HEATER (the two rightmost positions). There is no way to turn it off. This mod will disable that "feature":
You will need:
1. Phillips screwdriver
2. Soldering iron (or wire snips)
3. Electrical tape
If you remove the stereo and loosen the screws on the HVAC control pod, you will see a rocker switch that is activated when the dial is turned to DEFOG or DEFOG+HEATER. It's circled in red:
If you look at the underside of the switch, there are two purple wires soldered to the leads (one is disconnected in my photo):
Hold a soldering iron to one of the leads and pull on the purple wire until it pops off. Tape the end of the wire off and reassemble the console. Now the AC only turns on when you push the button.
If for some reason you want it back later, just resolder the purple wire to the switch lead.
**Note: I never removed the HVAC pod, I just pushed it up so I could reach the switch with my soldering iron. I have no idea how you get that pod out without breaking anything, so don't try.