Charging System: Description and Operation
Charging System
The charging system is a negative ground system consisting of the following components:
- Generator(s)
- Internal voltage regulator
- Charging system warning indicator
- Battery
- Circuitry and cables
Generator(s)
The charging system is a negative ground system. The generator is belt-driven by the engine accessory drive system. When the engine is started, the generator begins to generate AC current, which is internally converted to DC. This current is then supplied to the vehicle electrical system through the output (B+) terminal of the generator.
Gasoline, Single Generator
The gasoline single generator system consists of the generator mounted on the top center of the engine. A 120-amp generator with a 2.72:1 pulley ratio is standard. An extra heavy-duty option is available for 5.4L and 6.8L gasoline engines which includes a 155-amp generator with a 2.72:1 pulley ratio. A super heavy-duty option is also available for 6.8L gasoline engine which includes a 195-amp generator with a 3:00:1 pulley ratio.
The generators are similar in appearance and use the same connectors, making them interchangeable, although wiring lengths vary so a wiring change may be desired. Identification between the different generators can be carried out by referring to the generator engineering number and the parts catalog.
In the gasoline single generator system, the PCM controls the charging system warning indicator and commands the lamp on if the PCM detects a concern on the monitored circuits. The set voltage varies with temperature and is typically higher in cold temperatures than in warm temperatures. This allows for better battery recharge in the winter and reduces the chance of overcharging in the summer.
Diesel, Single Generator
The diesel single generator system consists of the generator mounted on the top right of the engine. A 110-amp generator with a 2.79:1 pulley ratio is standard. An extra heavy-duty option is available which includes a 140-amp generator with a 2.79:1 pulley ratio. The generators are similar in appearance and use the same connectors, making them interchangeable. Identification between the different generators can be carried out by referring to the generator engineering number and the parts catalog.
In the diesel single generator system, with the key in the ON position, voltage is supplied through the charging system warning indicator (in the Instrument Cluster (IC)) through the I circuit to the voltage regulator. The regulator grounds this circuit and the charging system warning indicator is illuminated. When the engine is started, the regulator removes the ground on this circuit and the charging system warning indicator turns off.
Diesel, Dual Generator
The dual generator package consists of an upper/lower generator system (diesel only). The 6.0L upper generator is a 140-amp generator with a 2.79:1 pulley ratio. The 6.0L lower generator is a 120-amp generator with a 3.00:1 pulley ratio. The upper and lower generators are not interchangeable.
The dual generators operate independently of each other. The control is through the internal voltage regulators. If one generator fails, the other generator can maintain system performance under light load conditions. Under heavy load, the PCM detects a concern, sets a DTC and illuminates the charging system warning indicator.
On the dual generator system, the PCM controls the charging system warning indicator and commands the lamp on if the PCM detects a concern on the monitored circuits.
Battery
The battery is a 12-volt direct current source connected in a negative ground system. The battery case is sealed and includes 2 vent holes to release gases. The battery has 3 major functions:
- Engine cranking power source
- Voltage stabilizer for the electrical system
- Temporary power when electrical loads exceed the generator output current