Alternator is one of the auto parts which an automobile cannot work without. It is electromechanical device that converts mechanical energy to alternating current electrical energy. It is the device which carries electrical power to essential car parts such as the headlights, the engine cooling fans, the radio, the ignition coil and many more.

It is true that batteries have the capability to run the machine and other electrical parts but its capacity cannot last long in a certain range of travel. This is the reason why the alternator is essential on all automotive vehicles. It can power up complex and more energy consuming auto parts that a battery cannot sustain. Thus the alternator cannot directly provide power without the battery and the fuel. It takes mechanical power from the crankshaft, transmits it via a serpentine belt and turns the alternator. It then converts the gasoline engine to electrical energy.

In cases when an alternator goes bad, the effect is not noted for a period because the battery does the job of providing power for the auto. It is then advised that some unnecessary power consuming parts should be shut down in this condition. Such parts are the blower motor, the stereo and headlights, the window defogger and specially the air conditioner. This step can save you from the use of a tow truck by using the battery power alone. As long as the energy is conserved, it can surely make it for some distance.

Here are some steps in diagnosing possible alternator problems. http://www.ehow.com/how_2210342_diagnose-car-alternator-problem.html