I have a very strange problem with my 08 Mazda5. The a/c only blows cold air from the two passenger side front vents. All other vents blow warm or hot air. The heater works fine with all vents. I can select all modes and it changes as it should. Everything appears to be working just fine except that cold air only comes out of the passenger side front vents.
Things I have done so far: Changed the cabin air filters, gained access to as many of the actuator motors that I can find, all work as they should from outward apperance. The rear a/c blows warm air as well.

 

Did you end up figuring this out because I'm experiencing the same problem now.