When traveling at highway speed in a head wind ( using full gas pedal at time the center A/C vent switchs to defrost nothing you do will re switch to center vent (you can turn off the A/C system, and when you turn it back on, it still is in defrost. No control will return A/C back to center vent) until you let off gas pedal and slow down, when this happens front windshield fogs up, blinding the drivers view of the highway. The dealers had to check the vacuum system and found no problem with the vacuum system, this is a off and on problem it will not do it all of the time, but when it starts there is no warning, I nearly had a accident while traveling back from miami to tampa.

- Pinellas Park, FL, USA