When the engine is running, the main current source - the generator provides electric current to all consumers, including the ignition system, and charges the battery.
If the red battery discharge warning light is on in the instrument cluster, it means that no current is supplied from the alternator to the on-board network and the battery energy is being used up. The operation of a car with a burning battery discharge warning lamp is unacceptable, since sometimes the cause of the lamp to light up can be a short circuit in the wiring, leading to a fire in the engine compartment of the car. Stop the car, turn off the engine and find out what malfunction caused the lamp to light up. If the cause of the malfunction was not a short circuit, and the battery was fully charged, you can drive to the garage without a generator, but it is better to try to fix the problem on the spot.
Checking electrical equipment
1. Check for a broken accessory drive belt. If there is a break, replace the belt (see «Accessory drive belt replacement»).
2. If the belt is intact, check its tension (see «Checking the accessory drive belt»).
3. After checking the belt, check the wires connected to the terminal «plus» battery...
4.... to the starter.
5.... and to the generator. Wires can be broken, broken inside the insulation, or with oxidized or unreliable contacts. Repair the problem and start the engine. If the charging current appears, you can continue driving.
6. If belt tension is correct, check fuse #69 (see «Location of fuses, fuses, relays and their replacement») in the mounting block of fuses and relays installed in the engine compartment. If the fuse is blown, replace it, start the engine and check if the low battery light goes out. If the lamp goes out, you can continue driving.
Warning: Do not install a fuse with a higher rated current, as this may cause damage to electrical equipment and even cause a fire.
If, after the measures taken, the discharge lamp continues to burn with the engine running, then the possible cause of the malfunction lies in the generator itself. There may be several reasons, and it is better to eliminate them in a car service or garage, and you can only hope that there is enough battery energy to get to them.
Helpful Hint: In order to reduce current consumption when driving a car with a faulty alternator, if possible, turn off the audio system, unnecessary lights, heater fan, rear window heating, etc.