Electrical circuit malfunctions

Circuit malfunctions may cause several automotive devices to become inoperative. There are only three electrical conditions that can cause an inoperative circuit.

These three conditions are number one an opened circuit. Number two would be a short and number three would be grounded.

Below I will explain each electrical problem in more detail. The reason that you should read the following page is because it will aid you in diagnosis when an electrical component is not working.

Whether or you are using a wiring diagram, or simply taking voltage checks on the vehicle, understanding the three primary reasons for failure is important.

Open circuit

Whenever there is a complete break or interruption in the normal current path, such as a break in the wiring from the source of power to the electrical unit or even within the unit itself, current will not flow.

In an automotive electric circuit, current normally travels through the wires or cables, through switches, and the device itself such as a starter motor or wiper motor.

A break anywhere along this route results in an open circuit and the complete loss of power. Some electrical manuals will describe this open as infinite resistance in the circuit.

And your automotive meter will read out of limits or OL. However, the symptoms will appear somewhat different than the typical high resistance circuit.

That is, there will be no heat created by this type of resistance, because there is no current flow or circuit load.

Also loose connections at terminals of the electrical device, broken leads or wiring within the device itself can cause an open circuit condition as well.

Keep in mind that even poor ground connections between the electrical load and chassis ground could be considered an open condition.

Open circuits depending on there type and location can easily create other mysterious circuit malfunctions.

Short circuits

The term short circuit is used to describe another type of problem or condition which can develop into an electrical circuits malfunction.

A short refers to a circuit that is completed in the wrong way, such as two bare wires touching each other, so the current bypasses part of the normal circuit flow.

Bypassing part of the normal circuit simply means that the current has found a path of least resistance and a higher current flow is the result.

This can result in a blown fuse, wiring or component overheating, burned parts of a wires installation and damaged electronic components.

A shorted electrical circuit causes more current to flow through the conductor than the conductor can handle.

Too much current known as an overloaded circuit causes the conductor to heat up. If the overload is severe or lasts long enough, the wire can melt.

The unique smell of burnt wiring insulation is always a sure sign of circuit malfunctions. Note that the wire can melt to the point where it disintegrates and causes an open circuit.

Grounded circuit

A wire touching ground may cause this, were part of the circuit within a unit comes in contact with the frame or housing of the unit.

In many situations electrical components will be case grounded. This simply means that the attaching bolts provide the system ground for the electrical circuit.

Deposits of oil, dirt and moisture around electrical connections or terminals, can provide an excellent path so that the current flows to ground.

This may also cause a grounded circuit condition. Remember that current flows through the path of least resistance in attempting to complete its circle back to ground.

These three types of circuit malfunctions are things that you will find as the root cause of your car electrical problems.

You should keep this in the back of your mind when you are using a wiring diagram to diagnose suspected electrically related automobile complaints.



Give this circuit malfunctions page a Then watch some of my exclusive car repair videos from the links below.



Learning more about the basic theory of electricity is valuable knowledge to have under your belt.

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