The contact owns a 2015 Chrysler 300C. The contact stated that while the vehicle was parked, after removing the car seat from the vehicle and attempting to fasten the seat belt, the seat belt failed to retract. The failure had occurred on the rear passengers side of the vehicle. A dealer was contacted. The vehicle was taken to the dealer and the contact was informed that there would be a charge for a diagnostic test to determine the cause of the failure. The vehicle was not repaired. The manufacturer was not notified of the failure. The approximate failure mileage was 193,000.