TL*THE CONTACT OWNS A 2007 BUICK RENDEZVOUS. WHILE DRIVING APPROXIMATELY 25 MPH, THE CONTACT REAR ENDED THE PRECEDING VEHICLE. THE DRIVER'S SEAT BELT DID NOT LOCK AND THE AIR BAGS FAILED TO DEPLOY. THE DRIVER INJURED HER CHEST AND LEFT KNEE. THE CONTACT DROVE THE VEHICLE TO THE DEALER AND THEY REPAIRED THE FRONT END OF THE VEHICLE; HOWEVER, THEY STATED THAT THE SEAT BELTS WERE IN WORKING ORDER. THE CONTACT WAS INFORMED THAT THE CRASH WAS NOT SEVERE ENOUGH FOR THE AIR BAGS TO DEPLOY. THE DEALER STATED THAT IF THE BRAKE PEDAL IS NOT DEPRESSED, THE SEAT BELT IS NOT SUPPOSED TO LOCK. THE MANUFACTURER STATED THAT SINCE THE DEALER STATED THAT THE SEAT BELT WAS NOT DEFECTIVE, NOTHING COULD BE DONE. THE FAILURE MILEAGE WAS UNKNOWN.