The generator features the following major components:

The slip ring and the frame are liquid cooled.

The generator features permanently lubricated bearings. Service should only include tightening of mount components. Otherwise, replace the generator as a complete unit.

The voltage regulator controls the rotor field current in order to limit the system voltage. When the field current is on, the regulator switches the current on and off at a rate of 400 cycles per second in order to perform the following functions:

At high speeds, the on-time may be 10 percent with the off-time at 90 percent. At low speeds, the on-time may be 90 percent and the off-time 10 percent.

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.

When the engine is running, the generator turn-on signal is sent to the generator from the engine control module (ECM), turning on the regulator. The generator's voltage regulator controls current to the rotor, thereby controlling the output voltage. The rotor current is proportional to the electrical pulse width supplied by the regulator. When the engine is started, the regulator senses generator rotation by detecting AC voltage at the stator through an internal wire. Once the engine is running, the 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 generator F-terminal is connected internally to the voltage regulator and externally to the ECM. When the voltage regulator detects a charging system problem, it grounds this circuit to signal the ECM that a problem exists. The ECM monitors the generator field duty cycle signal circuit. The system voltage sense circuit receives B+ voltage that is Hot At All Times through the HORN ALT / SENSE fuse in the underhood junction block. This voltage is used by the regulator as the reference for system voltage control. On vehicles that use a sense circuit connected to the voltage regulator, this circuit must be operating properly for the charging system work correctly, when there is a charging system concern all circuits at the generator should be tested.

The DIC displays a charging system message the when the following occurs:

BATTERY SAVER ACTIVE

The DIC displays the BATTERY SAVER ACTIVE message when the body control module (BCM) reduces or disables the performance of some vehicle systems in order to reduce the load on the charging system. The DIC receives a message from the BCM requesting illumination.

BATTERY VOLTAGE HIGH

The DIC displays the BATTERY VOLTAGE HIGH message when the IPC determines that the system voltage is greater than 16 volts. The IPC receives a message from the body control module (BCM) indicating the system voltage.

BATTERY VOLTAGE LOW

The DIC displays the BATTERY VOLTAGE LOW message when the IPC determines that the system voltage is less than 11 volts. The IPC receives a message from the body control module (BCM) indicating the system voltage.

SERVICE CHARGING SYS

The DIC displays the SERVICE CHARGING SYS message when the ECM detects a malfunction with the generator output. The IPC receives a message from the ECM requesting illumination.