The electronics in the car are responsible for many systems and subsystems. Lighting, audio systems, cooling, what’s there, you won’t even start the engine if the electricity goes out. Unfortunately, many drivers “swim” in this area and are not always able to cope with problems in the electrical circuit, despite the fact that often the problems are only associated with a blown fuse. This is a protective mechanism that often becomes unusable and disorientates drivers. In the material below we will discuss in more detail what a fuse is, how it works and how to replace it in case of failure of one of them.
What is a fuse?
A fuse is a special switching electrical device whose task is to disconnect a protected circuit by opening it or destroying (burning) previously provided conductive parts when an excessively high electric current passes through them. Roughly speaking, a fuse is a protective mechanism that self-destructs in the event of a threat to all electronics (in a car or electrical appliances). Some kind of self-sacrifice, if we talk metaphorically.
The principle of operation of the fuse
Automobiles use fuses and are selected in accordance with the rated permissible load. In the event of an emergency, when the voltage rises, the fuse box breaks and breaks the electrical circuit.
The self-destruction process starts in the event of:
- Short circuit - occurs if the insulation of the conductive parts has been violated or the devices have been improperly connected. The problem of frayed insulation cables in a car is generally one of the most common causes of blown fuses.
- Incompatibility of the power of the consumer device and the nominal current strength allowed for a particular electrical circuit. This problem is faced by those who decided to install additional electrical equipment in their car (lighting, radio tape recorders and others like them). Such powerful energy consumers are powered by basic wiring, which is not designed for such a high current value. Due to the excess of current power, the wires melt and lead to a short circuit, which fuses the fuses.
Fuse threshold
From the above it becomes clear that the fuse in the car is destroyed in case of exceeding the nominal value of electricity. The fuse part overheats and burns out.
The rated current of the fuse is calculated by the formula: Inom = Pmax / U.
- Inom is the nominal current value, which is measured in amperes;
- Pmax is the maximum possible load that this or that device can handle. Power is indicated on devices and measured in watts;
- U is the voltage level of the network. This indicator is measured in Volts. The voltage level in the car network is 12 volts.
Fuse types
Fuses are categorized by rated power, as well as by the size of the fuses themselves.
Fuses are divided by size:
- Micro are the most compact.
- Mini - a little more (16 millimeters).
- Norma is the usual size (19 millimeters).
- Maxi is the largest (34 millimeters).
Much more important is the separation by amperage. For convenience, they are all marked with certain colors, but you should not focus only on color, since in VAZ cars fuses are marked with colors different from those in foreign cars, because there are no standards in this area.
Fuse location
The first thing a motorist will have to face when trying to check the status of fuses or replace them is to search for a safety block. The fact is that figuring out where the fuse is located is not a trivial task. In different models of cars, the fuse box is located in different parts of the passenger compartment or even under the hood. Sometimes the number of fuses increases greatly, and the car manufacturer puts several blocks in different parts of the car. Because of this mess, it is simply impossible to offer a universal circuit or instruction for finding a safety block. For example, in domestically produced cars, fuses are located under the hood (a classic arrangement for the Lada). In foreign cars, the situation is more complicated. Fuses in the Toyota Corolla are located to the right of the steering wheel on the dashboard. It would seem that manufacturers of one country should be similar in their choice of arrangement of elements, but in reality everything is different. Fuses in the Nissan Almera are located to the left of the steering wheel in a small pocket.
Fuse check
A working fuse is first and foremost safety. Therefore, it is necessary to maintain them in working condition. If any element of the electronics in the car is out of order, it is necessary to check the operability of the part. How to do it? Many drivers simply access the fuse box and take out the fuses one by one to visually assess their condition. Car owners just look to see if the jumper in the fuse is damaged. Of course, this method works, but it is typical for amateurs, and besides, it is not always reliable, because the jumper can remain intact even if the fuse is blown. To check the condition of parts, it is better to turn on the circuit that has ceased to function (it can be any electronics, whether it be headlights, a stove or a stereo system), and then use a multimeter to check the voltage level in the fuse responsible for this circuit. Such a check will take much less time and give an accurate result.
Fuse Replacement
If the fuse is broken, it must be replaced immediately. First, we find the fuse box (if the box is located under the hood, the battery must be disconnected in advance). Remove the bolts from the cover of the safety block. With a 10 wrench, unscrew the nut that holds the clamp with wires. This is done in order to move them (they block access to fuses). Also, for greater comfort, you can dismantle the fuse panel, but this is not necessary. Then we simply remove the inoperative fuse and put in its place a new one (naturally, suitable in size and at face value).
Fuse Selection and Testing
When choosing which fuse you need, you need to keep in mind a number of conditions. When choosing a new part, you need to contact only trusted manufacturers who are responsible for the quality of their products. It is advisable to consult with other motorists who have identical cars and the load on the electric circuit. This is very important, since most fuses are manufactured in China, where no one controls this process. Due to poor-quality products, you can not only destroy the electronics, but the entire car. There were times when a fuse box burned out, but the fuses themselves remained intact.
To check the quality of the part, it is necessary to provoke a short circuit outside the car, and if the fuse blows, it means that it is of high quality and you can take the whole batch to replace the damaged ones in your car.
To create an artificial short circuit, you need to wind to the ends of the fuse along the wire, and then connect one of them to the plus, and the second to the minus and put on them an electric current with a voltage above the nominal.
Installation of additional equipment
If you plan to install additional equipment in the car, you need to find out whether the standard wiring of your car can withstand such a load. If not, then for new equipment it will be necessary to conduct a separate wiring, and the rated current of the fuse for it should be one and a half times higher than the rated current in the circuit. To calculate the load, you can use Ohm's law and special tables.