Where to tap speed sensor signal?

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Sorry SD, late response;
warning; tech babble ahead.

Was thinking the input to the sig-dyn unit was hopefully high impedance to not load the ecm output and a 10k 0r 47k resistor would separate the unit in case of a failure, somewhat like a fuse.
it would protect the ecm in case 12 volts were to become present on the white wire and limit the fault current to 1mA or less since i have no idea what the safe input level was to the ecm/instrument cluster and it is possible that the speed sensor has only 100 milivolts output if it is a reluctance sensor ( a small coil that picks up pulses from the abs tone wheel ).
On one diagram it calls the pulse input + and - on the abs unit, not sure what that means, hence the suggestion of an oscilloscope which displays the waveform and value of it rather than an average value on a multimeter, just to be on the safe side and not knowing enough about either unit.