Don't forget the hot dog method. Tie a string to the rear view mirror with a hot dog dangling on the end at screen height. Then fold a 3x5 card in half to make a 'V' and tape it to the middle of the string, with the two middle vents pointing at it. As the air blows, it will push the hot dog away from the screen, only to swing back and "press" the screen. Since it's capacitative, it could be a hot dog or your finger, the screen doesn't know. It happens frequently so the touchscreen never has a chance to hit it's 20min cutoff.