If the battery charging warning light remains on after starting the engine, turn off the engine and check the condition and tension of the alternator drive belt. If the generator drive is normal, then repair the generator.
If the regulated voltage does not exceed 13.5 V, check the generator. The following malfunctions are possible:
- failure of one of the diodes;
- phase failure;
- Charring or wear of the commutator.
Connect an accurate voltmeter to the battery terminals and start the engine.
Increase the engine speed and, after stabilizing the voltmeter readings, check that they are within 13.5-14.8 V. Turn on all electrical consumers (headlights, rear window heating, heater) and check the operation of the generator. In this case, the voltage generated by the generator should be in the range of 13.5-14.8 Volts.
If the generator voltage does not meet the required values, the cause of the malfunction may be worn generator brushes, weak brush springs, a faulty voltage regulator, a faulty diode, an open winding, or worn rotor slip rings.
Attention. When carrying out electric welding work on a car, be sure to disconnect the battery and relay regulator.