My ac unit isn't blowing cold air what could it be

I advise you to take to mechanic ASAP. This happened to me a week ago while traveling back home from Chrismas w family. Half hour later lost all ellectrical funtions driving 70+ MPH on interstate. No power steering, breaks, defrost etc. Stranded in strange city 4 hrs from home. (After towing 4 times -2 places said they could fix but when they saw car said they couldn't. 3rd place wanted $4000) $2000 to replace compressor, expansion valve, water pump and serpentine belt. If I had stopped at next exit for repairs when I first noticed, I would have avoided the most terrifying driving event of my life. Only 55,000 miles on my 2008 CX7 that I had seviced religiously. So if AC acts up in your CX7 drop everything and have pro fix immediately. Several years previous I received a recal notice from Mazda re AC. When I took it in they told me my AC OK so must not be affcted by problem. From my "research" so far this week. This is common in CX7. Good luck and please act fast.