coming home i noticed that the vents were blowing a bit hot but didn't pay attention. went out to check my headlights and started the car and again the vent air was hot. hit the ac button and still hot, moved temperature all the way down to lo and still was hot. but when you turn the ignition off and just let the fan blow, the air cools down. the engine temp is where it is and no problem in terms of overheating. i changed the water pump and flushed the coolant about 1000 miles ago and had no problem like this before. car is a 00 2.7 with only 40k miles any ideas?