Table of contents: Detecting damage in a circuit ↓ General recommendations ↓
To protect electrical circuits, they are used fuses with blade contacts, the color of which corresponds to the fuse protection current. The serviceability of the fuse is determined by the presence of a wire conductor connecting the fuse contacts. To replace a failed fuse, first turn off the corresponding electrical circuit, remove the fuse from the socket with tweezers. If the newly installed fuse immediately fails when voltage is applied, check the protected electrical circuit. If the fuse protects several circuits, connect them one by one in order to determine the faulty circuit by the blown fuse.
Detecting damage in a circuit
A typical electrical circuit consists of an electrical component, switches, relays, motors, fuses, circuit breakers, wires, and connectors that connect the electrical component to the battery and the body. To help you find the source of a fault in the electrical system, the manual provides vehicle electrical diagrams.
Before attempting to determine the source of a fault, study the relevant electrical diagram to obtain an understanding of the components of that circuit. The number of possible sources of fault can be reduced by checking the operation of other components in the circuit. If several components or circuits fail simultaneously, the fuse common to those circuits or components may be faulty, or the connection to the body - "ground" - may be broken.
The causes of the malfunction are loose or oxidized connectors, poor contact with the body, burnt out fuses or faulty relays. Visually inspect the condition of all fuses, wires, and connectors in the faulty circuit before checking the rest of the components. Use the electrical diagrams to identify the terminals that need to be checked to locate the source of the fault.
The basic tools needed to locate the source of the fault are a tester or voltmeter, a 12V test lamp, an ohmmeter, a battery and a set of wires with probes, a jumper, preferably with a circuit breaker or fuse, which is used to bypass the wires or elements being tested.
In addition to poor wiring connections, there are two other main types of faults that can occur in an electrical system: an open circuit or a short circuit.
The circuit is opened as a result of a break in the electrical equipment circuit, which interrupts the current and causes the electrical equipment element to switch off.
To check the integrity of the circuit, connect a circuit tester or voltmeter: one lead to the negative terminal of the battery or a grounded element, the other to the contact in the circuit being tested, preferably closest to the battery or fuse. In this case, the section of the circuit being tested must be under voltage from the battery, unless the battery connector does not conduct current or the fuse is blown (remember that some electrical circuits are only activated when the ignition key is turned to a certain position).
Turn on the circuit, then connect the tester lead to the connection closest to the circuit breaker on the side of the item being tested.
If there is tension (what does the control lamp or voltmeter reading indicate), this means that there are no breaks in the section of the circuit between the corresponding connection and the switch.
If a section is found where there is no voltage, then the circuit is open between this point and the point of the previous test where there was voltage. The open circuit is caused by a damaged or loose connector.
To detect the source of the short circuit, disconnect electrical consumers – lamps, electric motors, heating elements, etc.
Remove the appropriate fuse and connect the tester or voltmeter leads to the fuse terminals.
Turn on the power to the circuits, remembering that some electrical circuits are only turned on when the key in the ignition switch is turned to a certain position.
If there is voltage in the circuit (what does the control lamp or voltmeter reading indicate), this means that there was a short circuit in it.
If there is no voltage during the test, but the fuse still blows when the same load is connected, the load element has failed.
The negative terminal of the battery is connected to the "ground" - the body, engine or transmission. A poor or corroded mount can cause the component to fail or malfunction. Remember that many cars use "ground" wires between certain components, such as the engine/transmission, and the body, i.e. in places where there is no direct contact between metal components due to soft rubber mounts or a layer of paint.
To check the reliability of the element grounding, it is necessary to disconnect the battery and connect one of the ohmmeter terminals to a reliably grounded element. Connect the other terminal to the wire or connection to the body that needs to be checked. The resistance shown by the ohmmeter should be zero, if not, check the connection as follows.
If there is any doubt about the reliability of the contact with the "ground", disassemble the connection, remove dirt and clean the contacts. When reassembling, tighten the connector fastening, applying a layer of technical petroleum jelly or silicone grease to prevent corrosion.
General recommendations
Before removing electrical components or disconnecting electrical connectors, disconnect the battery after first finding out if you have a radio activation code.
Turn off the ignition and disconnect the ground wire from the battery.
After installing electrical components or electrical connectors, connect the ground wire to the battery.
Turn on radio and enter the code into it.
Raise the power windows all the way up. Then press all power window switches again for at least 1 second to the closed position to activate the power window control unit.
Set the time on the clock.