Recommendation. When searching for the causes of a malfunction of any of the electrical equipment devices, first make sure that its fuse is in good condition and that the contacts of the circuit connectors are secure. A common cause of electrical equipment malfunction is oxidation of the terminals of the connecting blocks. In this case, they must be thoroughly cleaned. Pay special attention to the connection points of the negative terminals of the electrical equipment with the vehicle's "ground". Often, it is the lack of reliable contact with the "ground" that leads to malfunctions in the electrical equipment.
To troubleshoot electrical equipment, you should use a tester - a combined electrical measuring device. Such devices come in several types: analog (with pointer indicator), digital (with liquid crystal display), universal (having both a pointer indicator and a liquid crystal display). When repairing a car, it is more convenient to use a digital device (or, as it is also called, a multimeter). It is compact and shows accurate values regardless of its position in space.
To check de-energized circuits, the multimeter is switched to ohmmeter mode. When measuring very small resistance (within a few ohms) it is necessary to make an adjustment - subtract the internal resistance of the multimeter, the electrical resistance of its wires and probes from the obtained value (usually 0.06-0.08 Ohm). To accurately determine this correction, you should switch the device to the mode for measuring small resistance values (up to 200 Ohm) and short-circuit the ends of its probes.
To check live circuits, the multimeter is switched to voltmeter mode (with a measurement limit of up to 20 V).
In addition, the multimeter allows you to measure the current consumed by the vehicle's electrical equipment (usually up to 10 A).
If it is necessary to determine only the presence or absence of voltage on a section of the circuit (without measuring the quantity), then it is more convenient to use a special 12 V indicator light...
...or a control lamp that you can make yourself (from a car lamp with a power of no more than 4 W, soldering two wires at least 50 cm long to it).
Note: The procedure for checking the technical condition of the vehicle's electrical devices is described in the relevant sections of the chapter.
Very often the reason for the failure of electrical appliances is the oxidation of contacts in the wiring harness pads, and to eliminate the malfunction it is enough to clean the pad terminals and treat them with a special conductive grease.
If any lighting fixture does not work (for example, a headlight, a turn signal, a light for the interior, etc), first you should check whether the lamp has burned out, and only then check the electrical circuits.
The algorithm for checking electrical circuits is common for all electrical appliances. First, check the fuse and relay of the inoperative appliance. Replace the blown fuse. If, when turning on the electrical appliance, the fuse protecting its electrical circuit burns out again, there is a short circuit in the wiring that must be urgently eliminated.
Warning! If you are not confident in your abilities, then contact a service station to repair electrical equipment, since unqualified repairs can lead to serious damage or fire in the vehicle's electrical wiring.
Further troubleshooting comes down to checking the electrical circuits (see "Electrical equipment diagrams") and to search for faulty elements (wires, switch, device) and their replacement or repair.
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