There are dozens of electrical components needed to route power in your vehicle’s electrical system and these can vary greatly according to vehicle make, model and age. Your electrical system includes your vehicle’s battery, alternator and starter. Many new vehicles also feature sophisticated computer systems that affect functions like steering, brakes, sensors, and more. All of these electrical components make it difficult to diagnose the cause of vehicle electrical problems, but most begin and end with your battery.

Batteries usually last between three and seven years, so it’s a smart idea to replace yours every four years as a safety measure. Have your vehicle’s electrical system checked immediately if:

• Your vehicle won’t start – you turn your key and hear clicking, grinding, or no sound at all
• Interior or dashboard lights do not illuminate properly
• Your vehicle runs well, but the headlights dim while you’re traveling at low speeds, or idling at a stop

Many critical problems can go unnoticed, and are almost impossible for even a certified technician to pinpoint without a professional diagnostic tool. And if your check-engine light is on, engine diagnostic services are the best way to determine exactly why. There are a number of possible reasons for an illuminated and/or flashing check-engine light:

• Regularly scheduled engine maintenance (such as an oil change) may be due
• Sensors or brake system may require reset or adjustment
• Engine, electrical, or vehicle computer performance issues

The horn is a safety device and should be fixed on your vehicle. Look in your owner’s manual to locate the fuse for this electrical circuit. If the fuse is not the problem, the electrical connections on the horn should be checked. You should also use a test light to see if you have 12 volts of power at the horn when the horn button is pressed. If you have power, then you have a bad horn. If you don’t have any power at the horn then the horn relay, bad horn switch, or a broken or corroded wire may be the culprit. Since some horn buttons are integrated with the air bags, I would leave disassembling the steering wheel for the professionals.

The battery may be defective or shorted. The alternator is trying to put out too much current. Alternators are not designed to run at 100% amperage output for long periods of time. They are designed to keep a battery charged as energy is used. Check to make sure you don’t have the polarity reversed on the battery. The red wire goes to the positive and the black wire goes to the negative. Trace the negative wire and make sure the ground connection is tight and not corroded. Be sure your battery terminal ends are also clean.