Wolf.Dose

Electric tachs are only in the A3 versions in Europe. However, they are povered by the standard mechanical cable. To my experience most the times the mech cabel is overbend somewere and the protective rubber hose is craced due to age. It is difficult to see, however, below it, the cable is rusted to the housing. So check the turning of the tach cabel on the tach side with the engine cranking. If the joint does not move, replace the cable. That the drive fails is almost unknown.
Wolf