Bulbs, though, are probably No. 1 on the replacement list because they're used so much and because there are so many of them. Most cars, for example, have at least three bulbs and usually more on each side for brakes, taillights, backup lights, turn signals and side marker lights. In front, there are headlights, maybe separate high beams, frequently daytime running lights and fog lights, turn signals, "parking" lights and side markers. Chances are that over time at least a couple of those will burn out or stop working because of corrosion or excessive jostling from rough roads.
You rely on your car's battery to start your car every time you turn the key. Whether you are driving to work or just hitting the road for a day of fun, you need to know that your battery is up to the job. Unfortunately, batteries don't last forever, and even new car batteries will eventually need to be replaced. How long should the battery in your vehicle last? The answer isn't always straightforward, and in many cases, it isn't as long as drivers think it should be.
Assuming that the battery is known to be good, then the next item to check is the battery terminals - the actual points at which the battery is connected into the electrical system. It is very important that these connections are clean and tight. This simple thing is often overlooked as a source of trouble, and is also a frequent cause of such trouble. Visually inspect the terminals, and clean andor tighten them if needed. To clean, use a small, stiff wire brush or a terminal cleaner which is made for the purpose.
When doing auto electrical repair, the first vehicle component your should acquire knowledge about is the car battery. Even though the battery only store 12 volts, it is the electrical source of the entire vehicle. You will not be able to start your engine without the battery. In addition the auto battery helps to operate all the electrical accessories installed on your motorcar. An auto battery should last 3-5 years in average climates. Extreme hot or cold climates however, will reduce this to only 2-3 years.