Repair of the speedometer and km counter by replacing the transducer.
The speedometer of the car did not work properly anymore AND the km counter did not count properly. Since I already soldered the speedometer and both indications failed, it had to be either a problem with the cabling or the transducer. I removed the transducer. This can be done by getting under the car. Remove the underplate and have a look on the axle going to the right wheel. In my case there was a small aluminium heat shield and the transducer. Remove the cable from the transducer by removing the little spring clip. get the connector out of the transducer and undo the bold holding the heat shield and the transducer. When getting the transducer out some gearbox oil can poor out of the hole, so be prepared. When replacing the transducer you can pull the gear with axle outoff the transducer and place that in the replacement transducer. That way you are sure the gear is appropriate for your car. I replaced the transducer with a secondhand transducer (€10) and put everything together again. Every thing worked fine afterwards.
Side view.
Top view
I could not resist to open the transducer. The round wheel is the rotating magnet. Next to the middle contact pin the hall sensor.
With the magnet removed it looks like this.