I have a 2002 F150 FX4 and it has the air conditioner that you can set to a temp and it will cool to that temp and adjust to remain the same temp (not sure what it is referred to). The A/C would blow out of the fron t vents as it is supposed to and a few months back it started blowing out of the dash/defrost vent when I would excel. Back then, I could swithch the controls and it would go back to normal for a while, but over time it will not switch back anymore. If I stop the truck and turn the A/C off and back on, it will blow out of the front vent, but only on low and as soon as I touch the gas pedal, it blows out of the dash vent again. This was not that big of a deal to me a few months agao, but the fact that I live in Texas, it is becoming a real problem. I have checked the fuses and dont see any problems there, but unsure what else to do. Does anybody know what could be causing this?