Speedometer works intermittently

If the speedometer is the only thing that doesn't work at times then most likely the issue is in the cluster. However, the trip meter is what we want to check to see if it is moving up steadily and accurately when the speedometer is not operating. You can track it with your phone to see it is close. If it is then the cluster is the issue. If not, then the vehicle speed sensor is the issue.

The way this works is the VSS sends signal to the cluster where it is converted into the display by the cluster. If the VSS is not reading accurately you will get erratic speedometer action or none at all.

Take a look at this information attached for more detail. Thanks