Something is wrong with my a/c. When i turn it on it only blows out of the top and bottom vents. Sometimes it will blow from the dash vents but thats only when i first crank the car. Soon as i start to drive it stops from the dash and goes to the defrost vent and the bottom vent by the pedals. I'm tired of my feet freezing. Does anybody know why? BTW, it doesnt matter what setting i put it on like vent, floor, norm a/c.