The contact owns a 2019 Ford Expedition. The contact stated that while driving at approximately 25 MPH, there was an abnormally loud popping sound coming from the vehicle, accompanied by a rotten-egg odor. The contact stated that the driver’s seat belt tightened and locked across the chest, rendering the seat belt inoperable; however, the contact was eventually able to unbuckle the belt. The contact had a headache due to the noise and left shoulder pain associated with the seat belt failure but had not sought medical attention. The contact stated that prior to the failure, the air bag warning light was illuminated. The contact had received notification of NHTSA Campaign Number: 26V344000 (Seat Belts). The dealer was notified of the failure, and an appointment was scheduled; however, the vehicle was not yet repaired. The manufacturer was notified of the failure, and the contact was provided a case number. The dealer and the manufacturer denied a request for a loaner vehicle. The failure mileage was approximately 152,000.