For 1990-2009 cars

Battery voltage is applied to the ignition switch at all times through circuit A2. When the ignition switch is turned to the START position, battery voltage is applied to the starter solenoid switch through the automatic transmission range switch. The automatic transmission range switch must be in the PARK or NEUTRAL position to allow the battery voltage to reach the starter solenoid switch at terminal C2.

When battery voltage is applied to terminal C2 of the starter solenoid switch, the pull-in coil and hold-in coil of the starter solenoid switch are energized with the pull-in coil grounded through the starter motor.

Energized coils work together to pull in and hold the plunger of the starter solenoid switch. As the plunger is pulled in, it closes the starter solenoid switch contacts and causes the shift lever to rotate, engaging the starter motor drive assembly to the flywheel.

With the battery voltage applied directly to the starter motor, through the closed solenoid switch contacts, the starter motor begins to rotate and engauges the drive assembly. The pull-in coil is de-energized by having battery voltage at both ends of the coil. The starter motor continues to rotate, cranking the engine through the drive assembly-flywheel gear combination.

The battery voltage is removed from the starter solenoid switch terminal C2 when the ignition switch is released from the START position. The hold-in coil is de-energized and the return spring in the starter solenoid switch causes the plunger to disengage the drive assembly from the flywheel. As the plunger returns, the plunger opens the solenoid switch contacts removing battery voltage from the starter motor.