Ford Focus Service Manual: Charging System

The charging system is a negative ground system consisting of:

• a generator with an internal voltage regulator.
• a charging system warning indicator.
• a battery.
• circuitry and cables.
• a PCM.
• a radial arm adapter (serviceable separately from the generator)

The generator is driven by the accessory drive belt. When the engine is started, the generator begins to generate AC which is internally converted to DC. The DC is controlled by the voltage regulator (located on the rear of the generator) and supplied to the battery. The PCM controls the voltage regulation set point, working with the generator internal voltage regulator over 2 control and communication circuits.