Troubleshooting the Electrical System [Toyota Land Cruiser J60]

A typical electrical circuit consists of a piece of electrical equipment, switches, relays, motors, fuses, fuse links or circuit breakers

switches and wires and connections that connect all the elements together and connect them to the battery and (ground) of the car. In order to simplify the process of troubleshooting in section 12 the electrical circuits of the vehicle's electrical system are shown. For example, the task of troubleshooting is significantly simplified if it is possible to check the serviceability of other consumers directly or indirectly connected to the suspected circuit.

If there is a failure of several consumers, then the most likely cause is a broken connection to ground or a blown fuse. As a rule, electrical equipment failures are caused by loose or corroded contacts, a blown fuse or a melted jumper. Troubleshooting is usually performed using a tester (voltmeter) or a test lamp, which are connected between the section of the faulty circuit and a well-cleaned ground.

By connecting a tester or a lamp in series along the circuit contour, you can identify a faulty section, which is detected by the loss of voltage or the lamp going out. To find a short circuit in the wires, you should remove the fuse of the circuit being tested and connect a lamp or voltmeter to the gap. A short circuit with ground is indicated by the lamp lighting up when the wires are swung from side to side (the tester should show voltage). To check the reliability of the connection to ground, connect through an ohmmeter (or via a control lamp with a battery) the tested wire connection to the ground and a well-cleaned section of the ground. If the ohmmeter shows a circuit (or the lamp will light up), then the ground connection is reliable. Otherwise, the ground contact is broken.

Keep in mind that in most cases the ground serves as a return current path connecting the circuit to the negative battery terminal. Therefore, a broken ground connection, or a break in the return current path to the battery, can be the main cause of failure.