A speedometer is an important instrument in a vehicle, as it allows the driver to know their current speed. If your speedometer is not working, it can be very frustrating and dangerous. There are a few things that you can do to try and fix a broken speedometer. First, check the fuse that supplies power to the speedometer. If this fuse is blown, then the speedometer will not work. Replace the fuse with a new one and see if that fixes the problem. If the fuse is not the issue, then there may be something wrong with the speed sensor or wiring. The sensor measures how fast the wheels are spinning and sends this information to the speedometer. If there is a problem with either of these, then the speedometer will not work correctly. You may need to take your vehicle to a mechanic to have them diagnose and fix this problem.