Tl* the contact owns a 2018 gmc yukon xl. while the contact was driving 20 mph, another vehicle crashed into the front passenger side of her vehicle. the contact's vehicle rolled into a ditch. the contact's son was seated in the third row seats on the passenger side in a car seat. the seat belt that was supposed to restrain the car seat did not remain steady. there were no warning indicators illuminated. the contact stated that the dashboard and steering wheel air bags did not deploy; however, the console, side curtain and rear air bags deployed. the contact sustained internal bleeding, lacerations, and liver injuries. her daughter was seated in the front passenger seat and sustained a fractured nose and facial marks from the air bag. the contact's son was seated in the car seat and sustained lacerations on his forehead. everyone was transported via ambulance to seek medical attention. a police report was filed. the contact associated the failure with nhtsa campaign number: 18v673000 (seat belts). the vehicle was towed to an impound lot. the vehicle was not diagnosed or repaired. the dealer and manufacturer were not notified of the failure. the failure mileage was 26,755.