The battery supplies voltage to the generator at all times. During engine start-up, the I/P cluster performs a bulb check by illuminating charge telltale for three seconds. The PCM supplies 5 volts to the generator L-terminal to initiate charging. The system charges the battery and provides power to the vehicle electrical devices. The PCM can increase idle speed to boost generator output if the battery voltage drops below specification. If the charging circuit malfunctions, the PCM signals the I/P cluster to illuminate the charge telltale.