Tire Sidewall problems of the 2005 Chevrolet Suburban

While driving our 2005 Suburban on the interstate, the check tire pressure indicator came on and immediately the back end became squirrelly. Pulling to the side of the road, the passenger side rear tire was completely blown at the sidewall. The tread caught onto the wheel well flare, causing about $500 in damage to the vehicle. The tire was original equipment on the Suburban, a p265/70r16 firestone wilderness radial. The VIN number on the Suburban is 1gnfk16233j164562. The tires had about 12,000 miles of usage when the blowout happened. I contacted gm (service request claim #1380514061) and had the service manager at john seretti Chevrolet in moon, PA inspect the tire. He could find no punctures, foreign objects or other evidence of external damage to the tire. Gm reviewed this and informed me that they did not have enough information to declare a defect, so they referred me to the tires manufacturer, firestone. The firestone shop in moon, PA also could not find any puncture or external damage. The manager there said the blowout could have happened for any number of reasons other than a defect and tried to suggest that it had been driven with too little tire pressure. That cannot be the case. The tires had been rotated and the air pressure checked by the dealership within the previous month and the vehicle is equipped with an air pressure sensor that warns of drops. That sensor went off at the same time the tire blew. Firestone sold us a replacement tire at a prorated cost based on the usage from the original.