GM Service Manual Online
For 1990-2009 cars only

Voltage is applied at all times to the ignition switch from the IGN A fuse 6 through the RED (242) wire. When the ignition switch is turned to the START position, voltage is applied to the CRANK fuse 8 through the YEL (5) wire. From the CRANK fuse 8, voltage is either applied to the clutch pedal position switch (M/T) or the transmission range switch (A/T) through the PPL (806) wire. When either the clutch is disengaged (M/T) or the transmission is in Park or Neutral (A/T), voltage is applied to the coil of the STARTER relay through the PPL (1035) wire. Since the STARTER relay is permanently grounded at ground G105 through the BLK (150) wire, the relay energizes.

Voltage is applied at all times to the STARTER relay contacts from THE IGN A fuse 6 through the RED (242) wire. When the relay energizes, the relay contacts close, and voltage is applied to the starter solenoid. Since the starter solenoid is permanently case grounded, the starter solenoid will energize two coils. The pull-in winding coil energizes in order to pull the starter solenoid contacts closed. When the contacts close, a plunger on the contacts causes the pull-in winding coil circuit to open. The hold-in winding coil then holds the contacts closed. Voltage is then applied to the starter from the battery through the BLK (1) wire and the closed contacts of the starter solenoid. Since the starter is also permanently case grounded, the starter will run until the ignition switch is moved out of the START position. When this happens, a spring in the starter solenoid moves the contacts and the plunger back to the rest position.