The contact's granddaughter owns a 2016 Jeep Cherokee. The contact stated while his granddaughter was at a stand still at a railroad crossing, the rear windshield shattered independently without impact. The contact stated he was not aware of any warning light was illuminated. The driver called the police department and filed a police report. The contact stated no one was injured nor seek medical attention. The driver was able to continue to drive to her residence. The contact spoke to the local dealer and made them aware of the failure. The contact stated an independent mechanic came to her residence and informed the rear defroster on the windshield overheated and burned the cables which caused the failure. The vehicle was repaired. The manufacturer had not been informed of the failure. The failure mileage was approximately 69,000.