Webasto Sunroof Module Troubleshooting

[Citroënbender]

Found a little more information. For better relevance, N35 is the sunroof module.

Pin 8 of N35 receives the automatic roof closure signal, in acordance with the …logic, coming from pin 10 of connector E of the Body Computer…

Pin 9 of N35 receives the speedometer signal from pin 23 of connector C of the Body Computer…

I think there are some possible language issues from the Italian here. Wondering if the “speedometer” in fact is the Hall effect pulse being sent back to the body computer. I know from past use you could operate the sunroof at pretty much any road speed from parked upwards. There’s no suggestion in the owner’s manual that it self closes at crazy speeds, either.

The “logic” is where I am particularly intrigued. As an analogue or possibly low speed comms line, is there a typical protocol to initiate a change of state? As in, is there a Vref that rests at zero and goes to +5 or -5 depending?