TL*THE CONTACT OWNS A 2007 CHEVROLET TAHOE. WHILE MOVING THROUGH A TOUCHLESS CAR WASH WITH THE VEHICLE IN PARK, THE REAR LIFTGATE OPENED. THE MACHINE SHATTERED THE GLASS. THE DRIVER AND FRONT PASSENGER SUFFERED HAND CUTS FROM THE GLASS. THE DEALER WAS UNABLE TO DETERMINE THE CAUSE OF FAILURE. THE CONTACT SUGGESTED THAT THERE WAS A BUTTON ABOVE THE LICENSE PLATE THAT LIFTS THE REAR GATE. THE CURRENT AND FAILURE MILEAGES WERE 10,000.