There are two sources of current in a car - a battery and a generator. The battery is used when starting the engine and for supplying the starter and other consumers with an electric current of 12 V when the engine is not running. 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 charging lamp is on on the instrument panel, then the current is not supplied from the generator to the on-board network and the battery energy is being consumed. This stock is limited and depends on capacity. If the battery has been fully charged, you can drive to the garage without a generator, but it is better to try to fix the problem on the spot.
1. Check if the alternator drive belt is broken.
If the belt is intact, check its tension. Press your thumb on the top of the strap and see how much it sags. Normal tension is provided when the belt deflection is 10–15 mm.
Normal belt tension?
Yes: see point 3.
2. Key on "17" loosen the nut that secures the generator to the adjusting bracket, insert a mounting blade between the generator and the engine block, and with this "lever" move the generator away from the engine. Tighten the alternator mounting nut.
3. Check if the appropriate fuse is blown. The location of the fuses and their ratings are indicated in this manual (see section "Electrical faults"), in the car repair manual, in a separate electrical diagram, on the cover of the mounting block and on the fuses themselves.
Blown fuse?
No: see point 6.
4. Replace fuse.
Warning! Do not install fuses with a higher rated current: this may damage the electrical equipment and even cause a fire.
Start the engine and check if the battery charging lamp is off.
Has the charging lamp gone out?
No: see point 6.
5. Bon Voyage!
6. Check the wire from the generator to "positive" battery terminal. Two wires are connected to it: a thicker one connects the battery to the starter, a thin one to the generator. The wire may be broken, broken inside the insulation, or have oxidized or unreliable contacts. Repair the problem and start the engine.
Got a charger?
No: see point 8.
7. Bon Voyage!
8. If, after the measures taken, the charging lamp continues to burn when the engine is running, then the possible cause of the malfunction lies in the generator itself. There may be several reasons, and it is better to use the help of a specialist to eliminate them, and you can only hope that the energy reserve in the battery is enough to get to the car service.
Tip: To reduce current consumption when driving a vehicle with a faulty alternator, if possible, turn off the radio, unnecessary lights, heater fan, defroster, etc.
Tip: Experienced motorists can be advised to check the generator voltage regulator.
The operation of the voltage regulator is to continuously automatically change the generator excitation current in such a way that the generator voltage is maintained within the specified limits when the generator speed and load change.
Vehicle check
To check, you must have a DC voltmeter with a scale of up to 15–30 V with an accuracy class of at least 1.0.
After 15 minutes of engine operation at medium speed with the headlights on, measure the voltage between the terminal "30" and generator weight. The voltage should be in the range of 13.6-14.6 V.
In the event that a systematic undercharging or overcharging of the battery is observed and the regulated voltage does not fit within the specified limits, the voltage regulator must be replaced.
Checking the removed regulator
- a) exhaust voltage regulator test circuit until 1996
- b) exhaust voltage regulator test circuit after 1996
Regulator (pos. 3), removed from the generator, is checked according to the above scheme. It is better to check the regulator, which was used before 1996, as an assembly with a brush holder, since in this case breaks in the brush leads and poor contact between the leads of the voltage regulator and the brush holder can be immediately detected.
Between the brushes, turn on the lamp (pos. 5) 1-3 W, 12 V. To conclusions "IN" (pos. 4), "B" (pos. 6) and to the regulator housing or terminal "weight" (pos. 2) connect power supply (pos. 1) first with a voltage of 12 V, and then with a voltage of 15–16 V.
If the regulator is working, then in the first case the lamp should be on, and in the second it should go out.
If the lamp burns in both cases, then there is a breakdown in the regulator, if it does not burn in both cases, then either there is an open in the regulator, or there is no contact between the brushes and the outputs of the voltage regulator.