i have a 05 FX4 and my AC worked fine all spring. now that its hot, my AC blows hot air. I went to PepBoys and got a freon recharge kit, and recharged it. Still no cold air. it blew colder for a few min, but now its back to HOT. Also, i just noticed when i turn the **** to defrost, it only blows air out of the dash vents, not out of the defrost vent. what the hell is goin on? any ideas? what do i do next ?