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For 1990-2009 cars only

Volts Indicator Lamp Always On Chevrolet/Oldsmobile

Starter

When the Ignition Switch is moved to the "START" position (and the Theft Deterrent Module recognizes the "Key Code"), battery voltage is applied to the Starter Solenoid (through the Theft Deterrent Relay). Both solenoid windings are energized. The circuit through the Pull-In Winding is completed to ground through the Starter Motor. The windings work together magnetically to pull in and to hold in the Plunger, which moves the Shift Lever. This action causes the Starter Drive Assembly to rotate as it engages with the Flywheel ring gear on the Engine. At the same time, the Plunger closes the Solenoid Switch contacts in the Starter Solenoid. Full Battery voltage is applied directly to the Starter Motor, which cranks the Engine.

When the Solenoid Switch contacts close, the voltage is no longer applied through the Pull-In Winding, as the battery voltage is applied to both ends of the windings. The Hold-In Winding remains energized, and its magnetic field is strong enough to hold the Plunger, Shift Lever, Drive Assembly and 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 CKT 6 wire and the junction of the two windings. Voltage is applied from the motor contacts through both windings to ground at the end of the Hold-In Winding. However, the voltage applied to the Pull-In Winding opposes the voltage which was applied when the winding was first energized. The magnetic fields of the Pull-In and the Hold-In Windings now oppose one another. The Return Spring causes the Drive Assembly to disengage and the Solenoid Switch contacts to open simultaneously. As soon as the contacts open, the starter circuit is turned off.

Charging

The Generator provides voltage to operate the vehicle's electrical system and to charge its battery. A magnetic field is created when current flows through the rotor. This field rotates as the rotor is driven by the Engine, creating an AC voltage in the stator windings. The AC voltage is converted to DC by the rectifier bridge and is supplied to the electrical system at the Battery terminal.

The Generator's Digital Regulator uses digital techniques to supply the rotor current and thereby control the output voltage. The rotor current is proportional to the width of the electrical pulses supplied by the Digital Regulator. When the Ignition Switch is placed in "RUN," voltage is supplied to terminal "L" turning on the Digital Regulator. Narrow width pulses are supplied to the digital rotor, creating a weak magnetic field. When the Engine is started, the Digital Regulator senses Generator rotation by detecting the AC voltage at the Stator through an internal wire. Once the Engine is running, the Digital Regulator varies the field current by controlling the pulse width. This regulates the Generator output voltage for proper Battery charging and electrical system operation.

The Powertrain Control Module (PCM) controls the Charge Warning Indicator bulb with a solid state lamp driver. The lamp driver turns on the bulb whenever it detects an undervoltage, overvoltage or stopped Generator.

Volts Indicator Lamp Always On Pontiac

Starter

When the Ignition Switch is moved to the "START" position (and the Theft Deterrent Module recognizes the "Key Code"), battery voltage is applied to the Starter Solenoid (through the Theft Deterrent Relay). Both of the solenoid windings are energized. The circuit through the Pull-In Winding is completed to ground through the Starter Motor. The windings work together magnetically to pull in and to hold in the Plunger, which moves the Shift Lever. This action causes the Starter Drive Assembly to rotate as it engages with the Freewheel ring gear on the Engine. At the same time, the Plunger closes the Solenoid Switch contacts in the Starter Solenoid. Full Battery voltage is applied directly to the Starter Motor, which cranks the Engine.

When the Solenoid Switch contacts close, the voltage is no longer applied through the Pull-In Winding, as the battery voltage is applied to both ends of the windings. The Hold-In Winding remains energized, and its magnetic field is strong enough to hold the Plunger, Shift Lever, Drive Assembly, and 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 CKT 6 wire and the junction of the two windings. Voltage is applied from the motor contacts through both windings to the ground at the end of the Hold-In Winding. However, the voltage applied to the Pull-In Winding opposes the voltage which was applied when the winding was first energized. The magnetic fields of the Pull-In and Hold-In Windings now oppose one another. The Return Spring causes the Drive Assembly to disengage and the Solenoid Switch contacts to open simultaneously. As soon as the contacts open, the starter circuit is turned off.

Charging

The Generator provides voltage to operate the vehicle's electrical system and to charge its Battery. A magnetic field is created when current flows through the rotor. This field rotates as the rotor is driven by the Engine, creating an AC voltage in the stator windings. The AC voltage is converter to DC by the rectifier bridge and is supplied to the electrical system at the Battery terminal.

The Generator's Digital Regulator uses digital techniques to supply the rotor current, and thereby control the output voltage. The rotor current is proportional to the width of the electrical pulses supplied by the Digital Regulator. When the Ignition Switch is placed in "RUN," voltage is supplied to terminal "L" turning on the Digital Regulator. Narrow width pulses are supplied to the digital rotor, creating a weak magnetic field. When the Engine is started, the Digital Regulator senses Generator rotation by detecting AC voltage at the Stator through an internal wire. Once the Engine is running, the Digital Regulator varies the field current by controlling the pulse width. This regulates the Generator output voltage for proper Battery charging and electrical system operation.

The Powertrain Control Module (PCM) controls the Charge Indicator bulb with a solid state lamp driver. The lamp driver turns on the bulb whenever it detects an undervoltage, overvoltage, or stopped Generator.

Volts Indicator Lamp Always On Buick

Starter

When the ignition switch is moved to the RUN position, battery voltage is applied to one side of the CRANK RELAY in the underhood electrical center through circuit 3, the PCM-BCM fuse in the fuse block, and the circuit 439. When the ignition switch is turned to START, voltage is fed to the powertrain control module connector C1 terminal 63 through circuit 5, the CRANK SIGNAL fuse in the fuse block, and circuit 806 through the underhood electrical center. Power is always provided from the CRANK fuse in the underhood electrical center to the common side of the CRANK relay contacts. When the powertrain control module sees the crank signal and determines that conditions are OK for a crank, it supplies ground through circuit 625 to the transaxle range switch connector C1 terminal G. If the gear selector is in either PARK or NEUTRAL, the ground continues through the transaxle range switch and circuit 1737 to the other side of the CRANK relay in the underhood electrical center. The CRANK relay now has both power and ground to the relay coil, causing the relay to pull in. When this happens, the power at the relay common contact is passed through the normally open contact and circuit 6 to the S terminal on the starter solenoid.

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

When the solenoid switch contacts close, voltage is no longer applied through the pull-in winding, as battery voltage is applied to both ends of the windings. The hold-in winding remains energized, and its magnetic field is strong enough to hold the plunger, shift lever, drive assembly and 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 circuit 5, the CRANK SIGNAL fuse, and from circuit 806 to connector C1 terminal 63 of the powertrain control module. The PCM then removes the ground from circuit 625, the transaxle range switch, and circuit 1737 to the CRANK relay. This causes the CRANK relay to release, opening up the relay normally open contacts. This removes the power from circuit 6 to the S terminal of the starter solenoid and the junction of the two windings. Voltage is applied from the motor contacts through both windings to ground at the end of the hold-in winding. However, the voltage applied to the pull-in winding opposes the voltage which was applied when the winding was first energized. The magnetic fields of the pull-in and hold-in windings now oppose one another. The return spring causes the drive assembly to disengage and the solenoid switch contacts to open simultaneously. As soon as the contacts open, the starter circuit is turned off.

Charging

The generator provides voltage to operate the vehicle's electrical system and to charge its battery A magnetic field is created when current flows through the rotor. This field rotates as the rotor is driven by the engine, creating an AC voltage in the stator windings. The AC voltage is converted to DC by the rectifier bridge and is supplied to the electrical system at the battery terminal.

The generator's digital regulator uses digital techniques to supply the rotor current and thereby control the output voltage. The rotor current is proportional to the width of the electrical pulses supplied by the digital regulator. When the ignition switch is placed in RUN, voltage is supplied to terminal L from the powertrain control module, turning on the digital regulator. Narrow width pulses are supplied to the digital rotor, creating a weak magnetic field. When the engine is started, the digital regulator senses generator rotation by detecting AC voltage at the stator through an internal wire. Once the engine is running, the digital regulator varies the field current by controlling the pulse width. This regulates the generator output voltage for proper battery charging and electrical system operation. Voltage is supplied at all times from the GEN fuse in the underhood electrical center through circuit 2740 to terminal S of the generator. This is used to provide a better battery voltage measurement. The powertrain control module also monitors the generator using terminal F through circuit 23.

The powertrain control module (PCM) controls the charge indicator bulb with a solid state lamp driver. The lamp driver turns on the bulb whenever it detects one or all of the following conditions:

    • When it detects an undervoltage.
    • When it detects an overvoltage.
    • When it detects a stopped generator.