I've got the factory service manual and it says to pull the dash off, drain the refrigerant from the AC system then pull the AC unit out of the dash and it's on the back there somewhere (It's been 6 years since I looked at it) I've seen pictures showing it behind the glove box somewhere but if I remember right it isn't like the pictures show.
That's why I didn't bother with it anymore after I pulled the plug off; I've been driving it for 6 years like that and I can't see any difference plug on or plug off, all the heater and AC works like it's supposed to (Even Max AC)