The power generating ability of the Volkswagen alternator is what provides the electrical current to keep your vehicle rolling down the road. The normal operating capacity of the alternator on a Volkswagen is a voltage output of 13 volts or greater. This is enough power to operate all of the electrical accessories and the engine and still have enough left over to charge the battery. The alternator on a Volkswagen engine receives it centrifugal power from the drive belt. If the drive belt is worn and slipping, it will have a negative effect on the power generation of this electrical unit. Because the alternator is an electrical component, it will also burn a circuit or fry a capacitor in time causing its ability to generate an electrical current to diminish or fail. A Volkswagen owner will notice this when the headlights are being used at night and the beam just does not seem to be as bright as it once was. When the accelerator is pushed down, there will also be a hesitation since the electrical current to the spark plugs will also be negatively affected. When either of these symptoms occur the Volkswagen alternator must be the primary suspect as the failing component. To confirm this situation of a reduced amount of electrical current, a voltage meter should be connected to the alternator and a reading taken. For a properly working electrical generator on your vehicle, it should be producing 13 volts or greater. When one begins to fail the power generation drops to just above 12 volts. When the voltage generation drops below 12 volts, the engine is partially operating off of the battery. Once the battery is drained of power, the vehicle will no longer be capable of running until an external electrical power source is found.