Anyone can change an electrical part. But how many automotive or truck service technicians can test and troubleshoot an electrical circuit on a vehicle.

The automotive electrical system in my opinion is the most important support system of a modern day car or truck. Imagine your own personal vehicle without an electrical system. The gasoline engine would not run. Electricity provides the needed spark for combustion, plus the power needed for starting.

Automotive electronics is a reference to computer control modules and other black box type items used to control engine operation as well as vehicle systems such as instrument clusters.

An electrical problem in a car stems from the nature of electrical circuits. An electrical device in a car must be part of an electrical circuit capable of providing the required voltage and current. If this is not the case, or if the device is defective, it will fail to operate as expected. There are three possible causes for an electrical problem.

You're driving along in your car or truck and suddenly a yellow light illuminates on your dash telling you to check or service your engine. If you're like most car owners, you have little idea about what that light is trying to tell you or exactly how you should react.

Ignore the warning, and you could end up damaging expensive components. It also can be a sign that your car is getting poor fuel economy and emitting higher levels of pollutants.

If the check-engine light comes on, here are some tips on what you should do:

• Look for a serious problem that requires immediate attention. Check your dashboard gauges and lights for indications of low oil pressure or overheating. These conditions mean you should pull over and shut off the engine as soon as you can find a safe place to do so. On some cars, a yellow "check engine" means investigate the problem, while a red "check engine" means stop right now.
• Try tightening your gas cap. This often solves the problem. Keep in mind that it may take several trips before the light resets. Some vehicles have a separate indicator that warns of a loose gas cap before the condition sets off the "check engine" light.
• Reduce speed and load. If the "check engine" light is blinking or you notice any serious performance problems, such as a loss of power, reduce your speed and try to reduce the load on the engine. For example, it would be a good idea to stop towing a trailer. Have the car checked as soon as possible to prevent expensive damage.
• Have the code read and the problem fixed. If you want to diagnose the malfunction yourself, you can buy a scan tool. Prices range from about $40 to several hundred, depending on the model and the features. The tools come with instructions on how to hook them up and decipher the codes. But unless you have a good knowledge of automotive diagnostics, you're probably better off taking the vehicle to a professional. Some automotive parts stores will read and interpret the code for you without charge. Unless there is an easy fix, they may simply refer you to a mechanic.