Most people focus on the size of the starter motor, but the solenoid is the component that does the heavy lifting in terms of logic and electrical switching. The solenoid has two jobs: it physically pushes the starter gear into the flywheel and it acts as a massive electrical relay to send current to the motor.

In heavy-duty applications, the solenoid is a frequent point of failure. Because it handles hundreds of amps, the internal contact discs can wear down or "stick" due to the heat generated by the electrical arc. When choosing a starter, check if the solenoid is "integrated" or "remote," and ensure it features a "soft-engagement" strategy. This prevents the gear from slamming into the flywheel, which reduces mechanical wear. A high-quality solenoid will also be fully encapsulated to prevent moisture from freezing inside during winter, which is a common cause of the dreaded "clicking" sound when you try to start a cold engine. Click here to know more.