How do you replace digital speedometer in a 1989 buick regal custom gs?

To replace the digital speedometer in a 1989 Buick Regal Custom GS, first disconnect the negative battery terminal to ensure safety. Remove the dashboard trim and the instrument cluster by unscrewing the necessary fasteners. Once the cluster is out, carefully disconnect the wiring harness and remove the speedometer from the cluster. Install the new speedometer by reversing the process, making sure all connections are secure before reassembling the dashboard.