Charging System

CHARGING SYSTEM

The charging system is a negative ground system consisting of the following:
- generator
- internal voltage regulator
- charging system warning indicator
- battery
- necessary wiring and cables

The generator is driven by the accessory drive belt.

When the engine is started, the generator begins to generate alternating current (AC) which is internally converted to direct current (DC). The DC current is controlled by the voltage regulator (located on the rear of the generator), and supplied to the battery.

The charging system voltage is controlled by the powertrain control module (PCM). The generator charges the battery, and at the same time supplies power for all of the electrical loads that are required. The battery is more effectively charged with a higher voltage when the battery is cold and a lower voltage when the battery is warm. The PCM is able to adjust the charging voltage according to the battery temperature by using a signal from the intake air temperature (IAT) sensor. This means the voltage setpoint is calculated by the PCM and communicated to the regulator by a communication link.

The PCM simultaneously controls and monitors the output of the generator. When the current consumption is high or the battery is discharged, the system is able to increase the idle speed.

To minimize the engine drag when starting the engine, the PCM controls the generator. The generator does not produce any output until the engine has started. The PCM then progressively increases the output of the generator.

The PCM controls the operation of the charging system warning indicator in the instrument cluster. The PCM is responsible for turning the warning indicator off after the engine is started and illuminating it under fault conditions (when the generator is not generating the correct amount of current with the engine running). The warning indicator will also be illuminated by the PCM at key ON engine OFF, and stall conditions.

Units are repaired as an assembly and not disassembled for repair.

The battery is a 12-volt DC source connected in a negative ground system. The battery case is sealed with 2 vents to release gases. The battery has 3 main functions:
- engine cranking power source
- voltage stabilizer for the electrical system
- temporary power when the electrical loads exceed the generator output current.

Circuit Description

Battery Output Terminal (B+) Circuit 30-BA6 (RD)
The generator output is supplied through the battery positive output (B+) terminal on the rear of the generator to the battery and electrical system.

A Circuit 30-BA10 (RD)
The A circuit is used to sense battery voltage. This circuit is also used to supply current to the generator field (rotor) and to turn on the voltage regulator which determines generator output. It is also used to turn the charging system warning indicator on if there is a fault in the charging system operation.

Circuit 5-EB6 (BU)
This is the generator communication (GEN COM) circuit. The PCM determines the optimal voltage setpoint for the charging system and communicates this information to the voltage regulator via the GEN COM circuit.

Circuit 4-EB6 (GY)
The generator monitor (GEN MON) circuit communicates the generator load and error conditions to the PCM.