How do i replace a faulty speedometer on a 1989 Volvo 740gl?

To replace a faulty speedometer on a 1989 Volvo 740GL, start by disconnecting the car battery for safety. Remove the instrument cluster by unscrewing the screws and gently pulling it out from the dashboard. Disconnect the speedometer cable and any electrical connectors, then replace the old speedometer with a new or refurbished unit. Reassemble the cluster, reconnect the battery, and test the new speedometer to ensure it functions correctly.