A starter motor with a piggyback solenoid such as this Nippondenso one will have two electrical connections. A large stud connects to a heavy cable running to the positive side of the battery. A smaller stud is connected to the ignition switch. When 12 volts is applied to this terminal, the solenoid closes and connects battery power to the starter motor terminal.A starter motor with a piggyback solenoid such as this Nippondenso one will have two elect You hop into your rig and turn the key, expecting your engine to turn over and come to life. However, all you hear is a click-click sound from under the hood. Was that a slow sounding turn of the motor or maybe an intermittent starting you had experienced a week ago? Well, now the starter just doesn’t want to turn and you’re going nowhere. There are several points of failure in your starting system that could be causing you trouble. Don’t immediately assume the starter is bad. A poorly charged or failing battery could be the cause, as could corrosion on terminals or degraded battery/starter cables. A second path of failure can be the 12V signal not making its way from the ignition switch (or associated relay) to the starter solenoid. To check if this path is functioning, simply use a scrap piece of wire to jump from the positive battery terminal to the small stud on the starter solenoid. If there is still no response from the starter, then it is probably at fault. Once you decide the starter is the culprit, you may decide to rebuild it yourself rather than getting a replacement. The most common wear parts on a starter are the two large copper contacts in the solenoid used to connect battery voltage to the starter motor. Sometimes these contacts can be replaced for a fraction of the cost of a rebuilt or new starter, and many of the other internal parts will continue to function fine for many miles. Inside the solenoid is this plunger. When electrical current is applied to the solenoid, this plunger moves to bridge two copper contacts inside the solenoid. In this way the solenoid serves as a high current switch to control the starter motor. Some vehicles, such as older Fords, have the solenoid mounted on the inner fender and not atop the starter motor.Inside the solenoid is this plunger. When electrical current is applied to the solenoid, t With the plunger removed, you can see the two copper contacts. One contact is connected to the battery cable stud, while the other runs to the starter motor. Each time the plunger touches the contacts, a little bit of the copper material is eroded by the electric arc so these contacts wear over time.With the plunger removed, you can see the two copper contacts. One contact is connected to Here is an example of a contact and plunger replacement kit that can be used to restore the reliable solenoid connection and function of this starter.Here is an example of a contact and plunger replacement kit that can be used to restore th By Jay Kopycinski Enjoyed this Post? Subscribe to our RSS Feed, or use your favorite social media to recommend us to friends and colleagues!