Determining the source of a fault. Mazda 3 (2003 release)

The electrical circuit consists of an electric element, switches, relays, motors, fuses, circuit breakers, wiring and connectors that connect the consumer with the current battery and body. For help in finding sources of malfunction in the electrical system manual are circuit diagrams of the vehicle.

Before you try to define a malfunction source, study the corresponding scheme of an electric equipment for representation reception about the elements of the chain. The number of possible sources of malfunction can be reduced by checking the work of other elements included in this chain. If some elements or chains fail simultaneously, might have a defective fuse, the general for these chains or elements, or a broken connection to the body - "weight".

The reasons for failure are weakened or oxidised sockets, breach of contact with a body, blown fuses or faulty relay. Visually check the condition of all safety locks, wires and sockets in the failed chain before to start check of other elements.

The main instruments necessary for detection of a source of malfunction, the tester or the voltmeter, control lamp 12 V, ohm meter, battery and set of wires to the probes, preferably with a circuit breaker or fuse, which is used for detour of checked wires or elements.

In addition to violations of wiring in the electrical system, there may be two main types of faults - disconnection or short circuit.

The circuit is opened due to breakage as a result of current is interrupted, causing electrical disconnection element.

To determine the integrity of the chain connect the device for check of schemes or voltmeter: one conclusion - to the negative terminal of the battery or grounded element, the other - to the contact in the circuit under test, preferably closest to the battery or fuse. Verifiable chain section must be energized from the battery, except when the connection plug to the battery does not hold a current or blown fuse (do not forget that some chains of an electric equipment join only at key turn in the ignition lock in certain position).

Include a chain, then connect the probe tester to the connection nearest to the switch on the side of the circuit under test element.

If there is a power (as evidenced by the fire of a control lamp or voltmeter indications), it means that on a chain site between corresponding connection and the switch no breaks.

If you find an area on which there is no tension, it means that an open circuit has occurred between this point and the previous check on which there was tension. Open circuit due to damaged or weakened socket.

To locate the source of the short circuit, turn off the electricity consumers - lamps, electric motors, heating elements, etc.

Turn on the power to the circuit; do not forget that some chains of an electric equipment join only at key turn in the ignition lock in certain position.

If there is tension in the chain (as evidenced by the fire of a control lamp or voltmeter indications), it means that the short-circuit.

If the test voltage is not present, and the fuse continues to burn when you connect the same load - damaged load cell released.

The negative terminal of the battery is connected to "weight" - the body, the engine or transmission. Loose or oxidised fastening can lead to component failure or malfunctioning. Do not forget that on many cars "mass" wires between some elements, such as the engine / transmission and body, that is, in those places where there is direct contact between metal elements because of soft rubber fastenings or a paint layer.

To check the reliability of grounding of an element it is necessary to disconnect the battery and connect one of the conclusions of an ohmmeter to reliably earthed element. Connect the other terminal to a wire or connection with a body that should be checked. Shown by an ohmmeter resistance should be zero, otherwise check the connection as described below.

If in doubt contact reliability with "mass", disassemble connection, remove dirt and clean contacts. When assembling tighten the mounting socket, which apply a layer of petroleum jelly or silicone grease to prevent corrosion.

Check the integrity of the wire in order to make sure that the chain, its land or conductive element. Disconnect the battery and connect the probe control lamp with its own power source, such as device for checking the integrity of circuits - one end of the chain, and the other probe to the second end of the chain. If the lamp lights up, it means that the chain is not interrupted, and conducts electricity. The switches can be checked in the same manner.