The method of tool inspection and lamp test is more suitable for checking the open circuit fault of conductor. When using the temporary lamp test method, it should be noted that the power of the lamp test should not be too large. When testing whether the control output terminal of the electronic controller has output and whether there is enough output, it should be especially careful to prevent the overload and damage of the controller. It is better to use diode test lamp.
Visual inspection method when a part of the automobile electrical system breaks down, there will be abnormal phenomena such as smoke, spark, abnormal noise, scorching, high temperature, etc. Through the hearing, touching, smelling and seeing of the human body's sense organs, the vehicle wiring harness and electrical appliances are visually inspected to determine the fault location, thus greatly improving the maintenance speed. For example, when the car line breaks down, there are often abnormal phenomena such as smoke, sparks, abnormal noise, scorching, high temperature, etc. Through visual inspection, the location and nature of the fault can be quickly determined.
Wire jumper inspection method: after a wire is short circuited to the suspected faulty line, observe the change of instrument pointer or the working condition of electrical equipment, so as to determine whether there is open circuit or poor contact in the circuit. Bridging refers to the operation of connecting two points of a circuit with one wire. The potential difference between two points of the circuit to be bridged is zero, not a short circuit.
The inspection method of instruments and meters uses comprehensive fault diagnosis instrument, multimeter, non wave device, current clamp and other instruments and meters to diagnose automobile circuit fault. For the electric control system automobile, the comprehensive fault diagnosis instrument is generally used to find the fault code to confirm the fault range of the vehicle; then the multimeter, current clamp or non wave device are used to check the voltage, resistance, current or waveform of the relevant circuit and diagnose the fault point of the wire of the outgoing harness.