So it was sure broken. Instead of making the wiper bend mod, I decided to try luck with a second hand one to see if it was good and, if not, make the wiper bend mod to this one.
Then, I tested voltage with +battery on pin 1, +meter on pin 2, -meter and -battery on pin 5. Voltage increased smoothly from 0.25 to 4.9 so the AFM need no refurbishment
But now the question arises. How to set CO pot? It should set with a CO meter I know, but I don't have one here and I have to put the new AFM.
I saw on this BMW TIS page the following information:
This reads that CO potentiometer on nominal position should give a voltage of 2.8V, I assume it's the factory default setting for the CO pot.
So then I proceeded to put +battery on pin 1, +meter on pin 3, -meter and -battery on pin 5, and then adjust the CO pot at 2.8V.
Would I install the AFM on car with this basic settings and later do a smoke test on a workshop? Could I run the car with this supposed factory default setting with no harm? Or should I put the AFM CO pot to the same voltage as the one currently installed on car?
Thanks!