Thank you for your reply!
But unfortunately, my TDI already has the electronic speedometer.
(With a single-line LCD display for kilometers traveled and an LCD clock.)
I think that, presumably, you can only replace the entire assembly in that case.
exchange -> expensive
Therefore, I'll just leave it as it is.
The vehicle's technical inspection (TÜV) is also not a problem.
All it needs is for the speedometer to work.
But what's even more interesting is:
The speedometer and tachometer seem to be something like stepper motors!
If, for example, the fuse for the cigarette lighter is defective, and you...
'When you turn off the engine, the gauges don't go to zero!'
When you turn the ignition back on, the needles suddenly jump.
'wild' back and forth. They seem to be getting calibrated or something.
