[Razorback1980]

Get a volt meter and a 4ft section of wire with alligator clips on each end. The starter motor needs 12+V on the large terminal of the solenoid. It also needs a good ground back to the negative post of the battery. When you turn the switch key, the small post on the solenoid should receive 12+V from the switch key. That's really all there is to it.

If you clip the 4 ft wire to the small post and then to the positive lead of the voltmeter and then the negative lead to a ground somewhere on the motor...when you turn the key to start, the voltmeter should read 12V. If it does the switch key is doing what it's suppose to. If not, then you need to check the large post of the solenoid to make sure it has 12+V. If it does then the starter is not receiving power back from the switch key to make the starter turn over and there is a connection break between the large post of the starter and the small wire coming back to the starter.