How do you fix speedometer on 1986 Volvo 740 GLE?

To fix the speedometer on a 1986 Volvo 740 GLE, first check the speedometer cable for any signs of damage or disconnection; replacing it if necessary. Inspect the speed sensor, located on the transmission, for proper function and clean any debris that may affect its performance. If the issue persists, consider checking the instrument cluster connections and wiring for faults. If all else fails, a replacement speedometer unit may be needed.