When my wire went bad, I could always start the engine by jumping (hot wiring) the solenoid with a screwdriver. This told me it was the solenoid wire that was the culprit. Later it got so frequent that I bought a
remote start switch with alligator clips for a sparkless start.
In each case, the engine would turn right over and start. If you have a bad "big cable" in the circuit, it won't behave differently when it's hot wired.