Did a bit shifting about and the situation is now, that I can hear a faint ticking noise in one of the sensors. So I swapped the 'good' one to a position where I didn't hear a ticking noise and it stopped working. Plugging the sensor, which did not work in to the working position stared working. I only did this on one sensor position, but would suspect the same on the other. It is difficult to get the middle sensors out. There is a plug between the harness for the sensors and the harness to the control unit. So I think it is not the sensors, it is either the harness to all the sensors, the harness from sensor harness to control unit or the control unit. Is it possible to check what to expect on the wire positions in the plug of the harness? Does anybody have a pin out, maybe I can easily check the harness?