Recommendation. When looking for the causes of a malfunction of any of the electrical equipment, first make sure that its fuse is in good condition and that there is reliable contact in the connectors of its circuit. A common reason for the inoperability of electrical equipment is the oxidation of the terminals of the connecting blocks, in which case they must be carefully cleaned. Pay particular attention to the connections between the negative terminals of electrical equipment and «weight» car. Often it is the lack of reliable contact with «weight» leads to electrical malfunctions.
Use a multimeter to troubleshoot electrical equipment. If it is necessary to determine only the presence or absence of voltage in a circuit section, without measuring the value, then it is more convenient to use a special 12 V light indicator...
...or a test lamp that you can make yourself (from a car lamp with a power of not more than 4 W, soldering to it two wires with a length of at least 50 cm).
Comment. The procedure for checking the technical condition of the vehicle's electrical appliances is described in the relevant sections.
Very often, the reason for the inoperability of electrical appliances is the oxidation of the contacts in the pads of the wiring harnesses. To eliminate the malfunction, it is enough to clean the terminals of the pads and treat them with a special conductive grease.
If any lighting device does not work (such as headlight, turn signal, interior light and so on), first you should check if the lamp has burned out, and only then check the electrical circuits.
The algorithm for checking electrical circuits is common to all electrical appliances. First, we check the fuse and relay of a non-working device, which, as a rule, are installed on the fuse and relay boxes. Replace the blown fuse. If, when you turn on the appliance, the fuse that protects its electrical circuit blows again, then there is a short circuit in the electrical wiring, which must be urgently eliminated.
Warning! If you are not confident in your abilities, then contact a service station to repair electrical equipment, as unqualified repairs can lead to serious damage or fire to the car's electrical wiring.
Further, troubleshooting comes down to ringing electrical circuits, which can be viewed on electrical equipment diagrams, searching for faulty elements (wires, switch, device) and their replacement or repair.