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 indicator light is on on the instrument panel, it means that the current is not supplied from the generator to the on-board network and the battery power is consumed. It is unacceptable to operate a car with a lit battery discharge warning lamp, as sometimes the cause of the battery charging lamp to light up may be a short circuit in the wiring, leading to a fire in the engine compartment. Stop the vehicle, turn off the engine and determine what is causing the battery charging light to come on. If the cause of the malfunction is 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 on a car
1. Check if the alternator drive belt is broken. If a break occurs, replace the belt and adjust its tension (see «Checking the tension of the alternator drive belt and replacing it»).
2. If the belt is intact, check and, if necessary, adjust its tension (see «Checking the tension of the alternator drive belt and replacing it»).
3. If even after tensioning the alternator belt, the battery charging warning light is still on, check the wires connected to «positive» battery terminal...
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 the alternator belt is tensioned normally, check if the F1 fuse in the fuse and relay mounting block has blown. If the fuse is blown, replace it, start the engine and check if the battery charge lamp goes out. If the battery charging lamp on the instrument panel goes out, you can continue driving.
Attention! Do not install fuses with a higher current rating. Doing so may damage the electrical equipment and even cause a fire.
If, after the measures taken, the battery charging warning light continues to burn with the engine running, then the cause of the malfunction may lie in the generator itself. There may be several reasons, it is better to eliminate them in specialized car services or a garage, and you can only hope that there is enough energy in the battery to get to them.
Checking the voltage regulator
To test the voltage regulator, you will need: flat and Phillips screwdrivers, wrench «at 12» (two), DC voltmeter, megohmmeter.
1. Pull out the rubber boot and connect the wire «+» to terminal «B+» generator, and the wire «-» to the generator housing.
2. Start the engine and turn on the headlights.
3. After 15 minutes of engine operation at medium speed, measure the voltage, it should be in the range of 14.4-15.1 V. If there is an undercharging or overcharging of the battery (voltage is out of range), replace the voltage regulator.