"N_Cook" wrote in message
...
Peter2 wrote in message
...

"N_Cook" wrote in message
...
Peter2 wrote in message
...


I was not told what its from. Googling I only found references to
overdrive
inhibitor switches not tachometer type sensors. So a standing 12V
across
them ?


Your description is an inductive tachometer pickup coil... I don't think
you
will find any biased with 12 volts across them either.



I hope gearboxes make good Faraday screens against ignition EMI, there is
no
braid screening around the signal wires though.



Generally twisted pair is used (at least on the ones that I work with), and
I've had little problems with EMI (though I do work primarily with diesel
trucks so EMI won't be ignition based at least). These same transmission
(for me) are used with gas engines however, so it appears to the designer
that EMI won't be an issue.