what he said is the skinny little wire that plugs into the started should get 12 volts (or light a test light) when someone is hold the keys in start/crank position. The big wire that attatches to the started with the 12mm bolt should have 12 volts (or light a test light) all the time because it comes straight from the battery.

If the skinny wire does as posted u got ignition switch problems more than likely.
If both test does as posted then u need a starter. (assuming ur stater is bolted down which is how the starter is grounded).

Good luck dood!!