Why is your odometer not working on 1991 miata?

If the odometer on your 1991 Miata is not working, it could be due to a faulty speedometer cable, a malfunctioning speedometer head, or an issue with the vehicle's electronic components if it's equipped with one. Additionally, worn gears inside the speedometer can also prevent accurate readings. Inspecting the cable for breaks or ensuring proper connections can help diagnose the problem. If these components are in good condition, it may be necessary to replace the speedometer unit itself.