Q: No start

Okay have a starting problem, one Technician told me to do a voltage drop test at the starter circuit to determine maybe wiring, short or starter, so I used a power probe put in "negative peak mode" at the starter relay circuit and cranked the car and the voltage dropped from 12.4 volts all the way down to 1.06 volts every time ,so am I right to assume it's a wiring problem not a starter problem, because when cranked engine turns a few inches & then stops without fully turning over? Battery terminals have already been replaced with a new battery.

My car has 165000 miles.