Every automotive electrical system consists of a battery, an alternator, a starter, and connecting wires. The nature of an electrical malfunction differs slightly depending on which component is faulty and most consumers are able to isolate basic problems with only a small amount of knowledge relating to how these parts work. Taking the time to learn about these four parts now could save you or someone you know a trip to your local auto mechanic.
A car battery contains a series of lead plates and some sulfuric acid that reacts with those plates in order to store electrical current. When the battery loses its charge, it is unable to supply the electrical current that the starter needs in order to get the engine working. When this happens, the automobile will fail to respond when the ignition switch is engaged. The most common causes of a dead battery include old age, a faulty alternator, a drain on the system such as a light that has been left on, and loose or corroded connectors.
If you think you might have a dead battery, the first step you will need to take is to pop the hood and make sure the connecting wires are fastened securely to the battery and are free of corrosion. If the wires look good then you can use a voltmeter to check the charge in the battery. To do this, place the voltmeter leads on battery's positive and negative leads. The voltmeter should register a charge between 10 and 12 volts. Anything less than this and you have probably found the source of your problem. An old battery can simply be replaced.
A dead battery that is relatively new and that should have many more years of service may be a sign that the problem exists somewhere else in the electrical system. At this point, you will want to reflect on whether or not a light or accessory was left on or plugged in while the vehicle was not being used. If this is the case, then your battery has probably been drained by the accessory or light. You can correct this problem by jump starting the vehicle.
If you have been noticing that your vehicle stalls or experiences dimming lights when stopped at a traffic light or stop sign then you may have a failing alternator. The alternator is designed to convert the mechanical energy of a running engine into electrical energy that is used to recharge the battery. An alternator that is not working properly will cause the battery to gradually lose its charge and eventually die. If the vehicle will start, you can assess the health of the alternator by checking the charge in the battery. If the voltmeter reads between 12 and 14 volts then the alternator is probably working fine.
The only other electrical problem that can be handled by the average consumer is a blown fuse. Signs of a bad fuse usually include electrical problems with a single set of lights or an accessory like the car stereo. Using your vehicle's manual, you can easily isolate the bad fuse and replace it with a new fuse of equal amperage. If the problem persists, then you likely have a much larger malfunction that requires the expert knowledge and skills of an auto electrician.
Electrical problems that are more complex than those outlined here usually should be left for the technician to assess and repair. Attempting to jump start a vehicle that is suffering from a complex electrical malfunction can cause more damage to the vehicle and can lead to expensive repair bills. If you are unable to determine the source of the problem or you are uncomfortable making simple repairs, the best idea is to make a trip to your local auto mechanic.