At its most basic, a short circuit is a fault in the wiring harness, which shunts electricity between circuits before getting to its destination. A short-circuit should not be confused with an open circuit, in which current does not flow at all. Though the symptoms of a short circuit can be similar to an open circuit, diagnosis is a bit different. There are several ways a short circuit can occur, and it isn’t usually easy to find and repair. To understand how to find a short circuit, though, we need to understand how a properly-functioning circuit works.

How Car Electrical Circuits Usually Work

There are many ways that electricity is carried around the car electrical system, and a short circuit could easily interrupt the proper flow of electricity in any of them. We can ro ... Read more »

The term spark ignition is used to describe the system with which the air-fuel mixture inside the combustion chamber of an internal combustion engine is ignited by a spark. The process uses an electrical field induced in a magnet or coil to build many thousands of volts that are collapsed via a timed circuit. The resulting surge of current travels along a wire and terminates at the spark plug inside the combustion chamber.

An electrical spark occurs as the charge tries to jump the precision gap at the tip of the spark plug at exactly the moment a precisely metered mixture of fuel and air — developed through atomization — has been thoroughly compressed in the combustion chamber. The result ... Read more »

If your car won't start or it hesitates when you crank it, you might have a bad ignition coil. Testing an ignition coil on most cars is pretty easy. No special tools are required, and you don't even have to remove the coil. Just remember to be careful, because the amount of electricity generated by your ignition system can be dangerous.

What the Coil Does

An ignition coil is a kind of high-voltage transformer. It converts the power from your car's 12-volt battery into the thousand or so volts that the spark plugs need in order to fire and then ignite the engine's air-fuel mixture. Although manufactured to last, ignition coils ... Read more »

It's easy to get frustrated when you get in your car and the engine won't turn over. Don't worry quite yet. If you're at home, there are three things you can test that will tell you what's wrong—and you might have an inexpensive repair on your hands. The most likely problem is a dead or drained battery. If that's good, then your battery cables might be dirty or your starter may be going bad. Rule these things out before you spend any time troubleshooting other possibilities.

Dead Battery

Just because you have a dead battery today doesn’t necessarily mean that you have to go out and buy a new one. Many batteries lose their charge or go ... Read more »

Keep in mind that an undercharged battery is often caused by car accessories being left on overnight, or by a rear compartment or instrument panel compartment lamp that stays on.

When the charging system is operating normally, the charge indicator lamp will come on when the ignition switch is turned ON and will go out when the engine starts. If the lamp does not come on with the key ON you will need to check the warning light circuit or replace the bulb.

Alternatively, noise from an alternator may be caused by the following components:

• Improper routing of hoses, wiring, or shielding against the alternator housing
• ... Read more »