Webasto Sunroof Module Troubleshooting

[Citroënbender]

Non-Ford problem, sorry.

20 year old Webasto sunroof power module - controller and motor. Doesn’t respond to input from control dial (either tilt or slide), doesn’t respond to actuation drive from diagnostics via body computer. Have tried another assembly, no change.

This is not a CAN module. It has four external inputs, permanent B+, permanent chassis ground, two wires from the body computer. The operating controls are looped from the assembly and use contact bridging combinations to drive the controller logic. The motor has a magnet on the shaft and two Hall effect devices to sense/count movement.

Given that it’s not a CAN node, I’m wondering what the likely inputs from the extra two wires are. Would one be a wake/sleep and the other a control for global commands?

[Falcon SXR8]

I dont have any specific details but i had one stop working and had to get an electronics fix it guy to fix the circuit board. Didnt cost much either from memory

[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?