Tacho o.F. ?

Hi everybody, slowly my Agi is getting old Now unfortunately I have a problem again !! My tacho doesn’t go anymore ! He has shrugged a bit then caught again. Since yesterday he doesn’t go anymore. The needle has just suspended in the stand between 0 – 20 km/h, when driving it then also back and forth. On the highway she then completely said goodbye and now does not work at all. can someone tell me vlt. what this is ? Thank you already and always good ride.