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The Starter Solenoid

April 03, 2019 3 min read

The starter motor in your car is made up of three main components. They are motor, Bendix drive, and starter solenoid. Car owners in Fort Lauderdale, Florida and Miami, Florida have access to expert mechanics who can closely examine starter motors when they fail in order to diagnose the problem. Often, it is a worn or faulty starter solenoid.


The starter solenoid’s full name is the starter solenoid switch. It controls the on/off function of the starter. So, if the solenoid cannot turn on, the car cannot be switched on. When you turn your ignition into the on position, the starter solenoid switch is fed electrical current by the battery. The starter solenoid switch controls the opening and closing of the electrical circuit. After the starter solenoid switch closes the circuit, the electrical energy creates an electromagnetic force. The electromagnetic force makes the gear in the motor start turning. The Bendix drive pushes the pinion gear out so that it engages with the engine’s flywheel. Once the car has started, the pinion gear disengages.


When the electrical current flows through the starter solenoid switch, it divides into two streams. The first flows through a sucking coil to make the electromagnetic force that allows the Bendix drive to push the pinion gear out so it can engage with the flywheel. The second flows through a holding coil to create a magnetic force that holds the pinion gear in place until the car has started.


The location of the starter solenoid switch


A starter solenoid switch is mounted directly on top of the starter motor. Starter motors are not placed in the exact same position in all makes and models of cars. However, they tend to be close to the car’s transmission system.


What types of problems may occur with a starter solenoid switch?


There are several things that can go wrong with your car’s starter solenoid switch.


  1. The suction into the sucking coil does not work properly. It works when your car is cooling down but not when the car is warming up.
  2. The solenoid cannot reset by opening the electrical circuit once it’s done its job. The starter, therefore, remains in operation after the car has started and only stops when the car is switched off.
  3. The return spring which controls the pinion gear weakens.
  4. The solenoid can make some abnormal sounds and fail to turn the crankshaft.


Figuring out what’s wrong with the starter solenoid switch


The first thing that any knowledgeable car expert would do is to test the solenoid using a multimeter. This indicates if there are any electrical problems with the starter solenoid switch. The entire electrical system in the starter motor needs to be checked if the multimeter reading is incorrect.


Many residents of Fort Lauderdale, Florida and Miami, Florida confess they wouldn’t even know where to start if they needed to test the solenoid with a multimeter. Here are some basic steps.


  1. Set the multimeter to continuity mode.
  2. Connect the probes: one to the solenoid shell and the other to the solenoid terminal.


Interpret the readings as follows:

  • If there’s resistance, the holding coil is functional.
  • If there’s zero resistance, there is a short in the circuit.
  • If there’s infinite resistance, there is a break in the circuit.