Three problems related to front seat belt have been reported for the 1999 Ford Mustang. The most recently reported issues are listed below.
Driver's side front seat belt and passenger seat belt will not retract and locks up. It appears that the seat belt will not work in an emergency as required. This has happened numerous times.
The front seat belts malfunctioned, they will either not release from holster, or when released will not retract back into the holster without excessive force being applied. This caused the belts to fray at the edges. Dealership will not provide any remedy or cause for this problem. Seat belts started getting hard to pullout and would not roll back up .
Both front and the rear passenger side seat belt failed to retract back into its holster when they were unfastened. Driver's side seat belt assembly was replaced, but the problem recurred.