Checking the generator (VW Sharan 1)

External manifestations of faults in the power supply system are as follows:

• no signs of battery charging;
• The battery discharges during operation, but there are no signs of generator malfunction;
• AB is recharging;
• the generator makes a lot of noise when running;
• the battery discharge indicator lamp does not light when the ignition is turned on.

If there are no signs of battery charging, then the reasons may be the following:

• blown fuse in the generator excitation circuit;
• weakening or damage to the alternator drive poly V-belt;
• break or short circuit in the wires;
• voltage regulator malfunctions;
• malfunction of the voltmeter or discharge control lamp circuit.

If the battery discharges during operation, but there are no signs of a malfunction of the generator, then the reasons may be the following:

• incorrect actions when turning on the starter;
• energy overconsumption;
• weakening of contact connections;
• insufficient voltage produced by the generator (due to a faulty voltage regulator or weak drive belt tension);

If the battery is recharged, then the reasons may be the following:

• the voltage regulator is faulty;
• short circuit of the generator excitation winding terminal to ground.

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If the generator makes a lot of noise while running, then the reason for this may be:

• breakage of one of the stator windings;
• rectifier unit failure;
• loosening the pulley mounting nut;
• contamination of contact rings and brushes;
• lack of lubrication in bearings.

You can only check the tension of the generator drive belt and the condition of the generator carbon brushes yourself. All other checks should be carried out at a service station.