almost every winter when I have to drive into deep snow a switch down near the transmission gets clogged up with ice and the car refuses to activate the starter , sometimes it is so bad I cant get the selector on the tiptronic to move out of park, if I tow it to a warm garage it thaws and all is fine. does anyone know what the switch is and have a part number for it ? this is an 98 A6 sedan.Thanks for your time.