Chances are when you are late to work or busy running all those errands you have put off, you are not thinking very much about the car that gets you from place to place. Unless you are an auto mechanic or someone who genuinely has a love of cards, chances are that you take your car's operation for granted and only really start to worry about it when something goes wrong – maybe you notice fluid leaking from the bottom of the car, or worse, perhaps you are in the middle of running your errands and the car suddenly does not start. That is when it is important to begin learning about the different parts that make your car run. One of those parts I the starter solenoid.
The starter solenoid, also known as the starter relay, is an auto part that has to do with actually starting the car. The starter solenoid sends a large electric current to your car's starter motor, and the starter motor then sets the engine in motion. In other words, when you are in the middle of running all those errands, you definitely want your starter solenoid in strong working order.
The starter solenoid receives the current it uses to help start the car from the car's battery. The car's battery, which generally uses 12 volts of power, is the car's main electrical power source. The starter solenoid does not receive its electrical power from the battery, though, it also receives a smaller electric current from the car's ignition switch. The next time you are in your car, take a moment to insert the key into the ignition and, before starting the car all the way, turn the key to the "on" position. You'll notice that some electric powered elements – such as the radio, the air conditioner and heat, or the windshield wipers – may come on. This is because the ignition switch just sent that small electric current to the starter solenoid.
You may be wondering what happened in your car when the starter solenoid received that electric current. Once that current was received, the starter solenoid closed a pair of heavy contacts. That signaled for a larger electric current to be sent to the starter motor. The starter motor, as opposed to the engine, is an electric motor that initiates the piston motion in a car's internal combustion engine. That, in turn, allows the car's engine to start running.
So what happens if your starter solenoid is not working? Well, first off, you will know because, most likely, your car will not start. If the starter solenoid receives inadequate power from the car's battery, it will fail in its task. The motor will not start. Instead, you may hear the car making a fast clicking sound. (Some call it a "clacking" sound.) Why didn't the starter solenoid get any power? There can be several reasons, most of them originating with the car's battery. For example, perhaps the battery is dead. This can be caused by leaving part of the car's electrical workings on when the car isn't running. (Headlights or interior lights are often a culprit in this case.)
The starter solenoid may also not get any power because the battery is severely corroded or because it has loose connections to the car. If any of these problems are present, it is possible that some, but not nearly enough, power will be sent to the solenoid. The clicking sound you hear is the solenoid attempting to start the car and failing. If the starter solenoid is the problem, it is best to let a mechanic diagnose it and then suggest a solution.