For 1990-2009 cars

### Starter Circuit Operation

When the ignition switch is moved to the START position, voltage is applied to the normally open contacts of the starter relay. Voltage is also applied through either the park neutral position switch (automatic transmission) when in park or neutral or the clutch pedal position switch (manual transmission) when the clutch pedal is depressed, to the starter relay coil. The body control module (BCM) energizes the starter relay by grounding one side of the relay coil only when the theft deterrent system has not been activated.

When the starter relay is energized, the normally open contacts close completing the circuit to the starter solenoid. When the starter solenoid circuit is completed, both the hold-in and pull-in windings are energized. The circuit through the pull-in winding is completed through the starter motor. The windings work together magnetically to pull in and hold in the plunger. The plunger moves the shift lever. This action causes the drive assembly to rotate as it engages the flywheel ring gear on the engine. At the same time the plunger also closes the solenoid switch contacts in the starter solenoid. Full battery voltage is then applied directly to the starter motor and it cranks the engine.

As soon as the solenoid switch contacts close, voltage is no longer applied to the pull-in winding since battery voltage is applied to both ends of the winding. The hold-in winding remains energized and continues to hold the plunger, the shift lever, and the drive assembly solenoid switch contacts in place to continue cranking the engine.

When the ignition switch is released from the START position, battery voltage is removed from the two windings. Voltage is applied through the motor contacts and both windings to ground. However, the direction of current flow through the windings is reversed. The magnetic fields of the two windings now oppose one another. The return spring, aided by the opposing magnetic fields of the windings, disengages the drive assembly which opens the solenoid switch contacts. Once the contacts open, the starter circuit is turned off.