GM Service Manual Online
For 1990-2009 cars only

With the ignition switch in the START position, battery voltage is transferred through the ignition switch to the clutch pedal position (CPP) switch (manual transmission) or the transmission range switch (automatic transmission). When the clutch pedal is depressed, the CPP switch is closed and battery voltage is applied to the starter solenoid windings. When the manual selector lever is in the P or N position, the transmission range switch is closed and battery voltage is applied to the starter solenoid windings. In each case this causes the shift lever to push out the drive assembly, engaging it with the flywheel ring gear. This movement also causes the starter solenoid contacts to close. With the contacts closed, the starter solenoid provides a closed circuit between the battery positive (+) terminal and the starter assembly. Because the starter assembly is permanently grounded to the engine block, the circuit is complete and cranking occurs as soon as the starter solenoid contacts close. When the engine starts, the drive assembly is designed to overrun and protect the armature from excessive speed until the ignition switch released from the START position. With the ignition switch released, voltage is removed from the starter solenoid and the windings de-energize. When the starter solenoid de-energizes, the return spring in the starter solenoid forces the contacts open, breaking the circuit between the battery and the starter solenoid, and disengages the drive assembly.