Generator/Charging System — In-Car Check (Audi 100 C3)

1. If the charging indicator lamp does not light when the ignition is on, first check the generator wiring for proper connection. If the wiring is OK, check that the indicator lamp is not burnt out and that the bulb socket is correctly positioned on the dashboard. If the lamp still does not light, check the integrity of the wiring from the generator to the bulb socket. If the test result does not show any damage to the wiring, the generator is probably damaged.

2. If the alternator indicator light comes on while the engine is running, turn off the engine and check that the drive belt is not damaged and is properly tensioned, and that the alternator connections are secure. If all is well, check the alternator brushes and rings as described in Chapter 6. If the alternator still does not work, it should be replaced or have an auto electrician check and repair it.

3. If a fault is suspected at the generator output even when the test lamp functions correctly, the regulated voltage can be checked as follows.

4. Connect the voltmeter to the battery terminals and start the engine.

5. Increase the engine speed until the voltmeter readings stabilize. The voltage should be approximately 12-13 V, but not more than 14 V.

6. Turn on as much additional electrical equipment as possible (for example, headlights, rear window defroster and heater blower) and make sure that the generator maintains voltage within 13-14 volts.

7. If the regulated voltage is outside the specified limits, the fault may be due to worn brushes, weak brush springs, a faulty voltage regulator, a faulty diode, a disconnected winding, or worn or damaged alternator rings. The alternator should be replaced or taken to a specialist for inspection and repair.

This publication is borrowed from the resource AUDIMANUAL.ru