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Electrical circuits

The usual electric chain consists of elements of the electric equipment, switches, relays, motors, fuses, fuse links and connectors and cables that connect all the elements together, the battery and the "weight" of the car.

The cause of the fault can be found much faster, if it is determined which of the elements of this chain work normally. If a failure of some elements or chains, the problem probably lies in a blown fuse or bad grounding as frequently one safety lock protects some chains.

Problems with the operation of the electrical system are usually caused by the simple reasons, such as oxidised or unreliable contacts, blown fuse, fuse burned out or faulty relay. Visually check the condition of all safety locks, wires and sockets in the affected circuit before checking other elements of this circuit.

The main instruments necessary to detect a fault in the circuit are:

- The tester or voltmeter (or lamp 12 V with connecting wires);
- Indicator lamp with power supply (or a device for checking the integrity of the chain);
- Ohmmeter (for resistance measurement);
- accumulator battery;
- Probes with wires;
- Cap the wire, preferably with a circuit breaker or fuse, which can be used to check the wiring or elements of the electric equipment.

To detect a bad connection or the fault location (usually because of a bad connection or dirty, or damaged insulation) wires can be shaken by hand to see if the circuit does not go out of operation at wire movement. In this way, one can find a point with fragile connector or the point at which a short circuit occurs.

In addition to problems associated with an unreliable connection, the electrical circuit may have two other major fault - an open circuit or short circuit.

Open circuit may be caused by the disruption of any wires or absence of compound in the chain, which would prevent the flow of current. Open circuit will cause the failure of any item of electrical equipment in the work, but will not result in a blown fuse protects the circuit.

Problems with the short circuit caused by the closure of the circuit, which leads to the fact that the current flowing through the circuit begins to flow in the other circuit, and more often, goes to "mass". Short circuit is usually caused by rupture of isolation, allowing the power supply wires to touch any other conductor or a grounded element, such as a body. Short circuit causes a blown fuse protects the corresponding chain.

Before looking for the source of a fault or during repairs in the electrical system, be aware that different types of cables have a different color.

To detect open circuit, connect one lead of a control bulb to the negative terminal of the battery or the "weight" of the car.

Connect the other probe to connection in a checked chain, preferably located as close as possible to the battery or fuse.

Apply power to the circuit. Do not forget that in some circuits the voltage is applied only when you turn the key in the ignition lock in certain position.

If pressure is present (about what the lighted up will testify control light or voltmeter indications), it means that part of the chain between the compound and the battery is working.

Continue to check the rest of the circuit in the same way.

When the point is found where the voltage is absent, it means that the source of the fault lies between this point and the previous point, where the voltage is present. Most problems are caused by bad connection.

The negative terminal of the battery is connected to the "weight" of the car - to metal engine / transmission and body of the car - and the majority of systems of electrical equipment are designed to fit a piece of equipment only one power cord, and current returns through the metal body of the car. This means that the electrical mounting element and the vehicle body are part of the electrical circuit. Therefore, bad or oxidised fastening can cause a large number of problems in the electrical system, the output of the full circuit of the system to its precarious work. In particular, bulbs can burn dimly (especially if you include another circuit using the same point of the earth), motors (eg wiper motors or the radiator fan) can work slowly and the inclusion of any chain can influence the work of other chain. Note that on many cars connecting earthing strips between the different units of the automobile, for example, between the engine / transmission and body, that is, usually when there is no metal between the contact elements due to the use of rubber mounts, etc.

To check the reliability of grounding disconnect the battery and connect one lead of an ohmmeter to the "weight" of the car. Connect the other test lead to a wire or ground point to be tested. Resistance recorded by an ohmmeter should be equal to zero; otherwise, check the connection as follows.

If you think that the connection is not in order, disassemble connection and smooth out to pure metal contact surface and the surface of the terminal wires or grounding element. Completely remove dirt and corrosion, and then, using a knife to remove the layer of paint in order to obtain reliable metal-to-metal connection. During assembly, firmly secure connection; When installing the terminal wires, use toothed washers between the plug and the body. After connecting, to prevent corrosion, apply a connection layer of vaseline or silicone grease.