1. First of all, check the condition of the wires and their connections, the fusible link, the integrity and tension of the drive belt.
2. Check the voltage on the battery with the engine stopped, which should be about 12V (see photo).
3. Start the engine and check the voltage again, which should be between 14 and 15 V.
4. Turn on the headlights. With a working charge system, the voltage should drop and then recover to normal.
5. If the voltage reading is higher than specified, replace the voltage regulator. If the voltage is below normal, then the generator diodes, the stator are faulty. Voltage regulator.