Starters are an important part of any vehicle, regardless of make or model. In order to start your car, the starter must be able to kick over your engine. Of course if your starter is clicking or not working properly, you may be wondering just how starter solenoids work.
Of course if you just want to get back on the road, our guide to testing starters can definitely help. Before we get into our FAQ on how starter solenoids work, you may want to check out our other guides on starters themselves.
How starter solenoids work
Before we get into this FAQ, you should understand what a solenoid really is. A solenoid is an electromagnetic device that is capable of doing a job. In this case or this FAQ, the solenoid we are looking at is the one on your starter.
In many cases, the starter solenoid is merely a switch or something that gets the job done. For most vehicles, this means that the solenoid activates or makes the starter do it’s job. For traditional starters, this means that the starter solenoid moves a plunger that makes electrical contact between terminals for the battery and starter.
Inside your starter solenoid there are two housings with wire coils. These coils act differently and perform different jobs for your starter.
The main coil draws a lot of current and produces the magnetic field your starter needs to get the job done.
The small coil draws a small amount of current and produces a weaker magnetic field—just enough to hold the coil in position. These two coils are at the heart of how starter solenoids work in your vehicle.
Before you insert your key and turn the ignition, the starter gear and plunger are held within the housing. This is done by the smaller magnetic field created by the secondary coil. Once you crank the ignition, the starter solenoid will jump the current and activate the larger coil.
This causes the motor to engage, sending the starter gear and plunger in motion. Once the plunger is in position the large coil is disconnected and the circuit for a small coil is completed. Why does this happen you ask? Well, this ensures that the battery has enough juice to crank the engine, which is the real job of the starter.
Should there be insufficient power to crank over the engine, you should hear the starter solenoid click. This clicking sound is the sound of the plunger moving back into the starter housing. This is in essence how starter solenoids work in a nutshell.
If you have already checked out our guide on how to test your starter, you should check your terminals. The battery and starter terminals play a huge role in how starter solenoids work overall. Make sure to check terminals for corrosion and physical damage.
If the corrosion is minor, you may be able to remove the retaining nut and battery cable and wire-brush corrosion away. If there’s extensive damage to the terminals, use this time to replace them properly.