TL* THE CONTACT OWNS A 2007 GMC YUKON. THE CONTACT STATED THAT THE AUTOMATIC LIFTGATE WAS OPENED AND THEN ABRUPTLY RELEASED, STRIKING THE CONTACT ABRUPTLY ON THE HEAD. THE CONTACT SUSTAINED A CONCUSSION FROM THE FORCE OF THE IMPACT. THE CONTACT STATED THAT THE REAR LIFTGATE HAD ONLY BEEN OPENED THREE TIMES SINCE PURCHASING THE VEHICLE AND IT WAS FOUND THAT ONE OF THE SUPPORT STRUTS HAD DETACHED FROM THE LIFTGATE. THE VEHICLE WAS NOT REPAIRED. THE MANUFACTURER WAS NOT NOTIFIED OF THE DEFECT. THE APPROXIMATE FAILURE MILEAGE WAS 50,000.