Your ignition switch (key switch) will have more like 5 or more wires, there is likely a plug on the back of it, Unplug it and re-plug it see if things then work...
You Should have the Same voltage as the Battery on the Large terminal of the starter solenoid.
With the Key switch held to start, you should have 12 volts applied to the Small terminal on the starter solenoid. That is what energizes the starter solenoid.
the starter solenoid can be checked By jumping from the battery positive to the Small terminal On the solenoid... if the battery is good, and the starter is good, and the battery cables are good... it will crank the engine. :smile:KennyV