How do you find a break in a cable?

[kg]

that's exactly what i'm saying.

the proximity to each other will cause signal to appear on all three.

remember you're not loading it down in any way... those wires are floating and they'll quite happily change their voltage, which ends up getting picked up by the sensor.

by grounding 2 of the 3 you'll be certain that no signal will appear after the discontinuity (or very very little signal, at least).

[Krwkka]

Thanks for the tip. I'll report back after I try it.