Inhibits engaging overdrive if too slow a gear wheel or in this case broken
wires to the sensor. Looks as though transmission fluid makes the wiring
sleeving go hard and brittle then vibration completes the job. No I don't
know what its from , built into a 3/8 UNF stud though so localises it a bit
I suppose .
Is the system passive or active.? Magnet as a pole piece inside a coil
probably, 330 ohm, 60nH. Spinning a steel cog in a drill , passive output is
about 10mV sineish pk-pk 5mm from gear and about 100mV if 3mm from the gear.
But also a lot of EMI from the drill motor so are these things used actively
?