Where you driving, or parked?
The problem with my Explorer is only when parked or stop-start traffic (in the sun), and very hot (above 100F). We had the car parked outside this morning, at 43c (109.4), and after starting up, and 10 minutes waiting, the vents would just not blow cold air, this despite the temp setting is on Lo and the fan's in the engine compartment where working. The air is a little cool coming out of the vents, but not cold enough to provide comfort. Auto or manual setting does not matter. 2 minutes after driving; the air from the vents is ice cold.... but stopping again, at it gets soon warmer again. The car has been 3 times checked now, and nothing wrong was found; the SA told me its normal for this car.
EDIT: I just went outside and did a quick check with the temp probe. Outside temp is 41c now (106F). While parked (15 minutes) the air temp on the vent never goes below 14.4c (58F). This is not cold enough to get comfort in the cabin. As soon I drive, 30 seconds later it is already on 7.7c (45.8F), wich is how it should be all the time. As mentioned earlier, all the cooling fans in the engine compartment are working. I suspect that the AC design / capacity is not cooping with the high temps in this country; this despite my Explorer is Gulf Spec. I am glad we get cooler weather next month....