Quick question: Is it an on-and-off thing, or does it not blow cold air at all? I lack technical expertise because I=n00b.
However, if it's anything like when I was in Phoenix and Flagstaff in Arizona, its just a matter of giving it a while to get going. The desert isn't too friendly to our Z cars...the heat is a compouding problem to the coolant/overheating issues we already face.
Personally, I just rolled down the windows and embraced mother nature giving me the middle finger.