Owner notification began november 16, 1999. Owners who take their vehicles to an authorized dealer on an agreed upon service date and do not receive the free remedy within a reasonable time should contact buick at 1-800-521-7300 or cadillac at 1-800-458-8006.also contact the national highway traffic safety administration's auto safety hotline at 1-888-dash-2-dot (1-888-327-4236).