The wiring harness is the wiring part that connects the electrical equipment in the car circuit, and it is composed of an insulating sheath, a terminal, a wire, and an insulating wrapping material. In order to facilitate installation and maintenance, and to ensure that electrical equipment can work under the harshest conditions, the wires of different specifications and colors used in the electrical equipment of the whole vehicle are arranged in a reasonable manner, and they are integrated, and the wires are bundled with insulating materials. Bundles are complete and reliable.
1) Detection and judgment of wire harness burnout failure
The burnout of the wiring harness happens suddenly, and the burning speed is very fast. Generally, there is no safety device in the burnt out circuit. The law of wire bundle burnout is: in the circuit of the power system, where the wire bundle is grounded, the wire bundle burns wherever it is. The junction between the burned out and the intact part can be regarded as the wire grounding; if the wire bundle is burned out When it reaches the wiring position of a certain electrical equipment, it indicates that the electrical equipment is faulty.
2) Detection and judgment of short circuit, open circuit, and poor contact between lines
The wire bundle is squeezed and impacted from the outside, causing damage to the wire insulation in the wire bundle, causing a short circuit between the wires, causing some electrical equipment to lose control and the fuse to blow.
When judging, you can disassemble the electrical equipment and the wire harness connectors at both ends of the control switch, and use an electric meter or test lamp to detect the short circuit of the circuit.
In addition to the obvious breaking phenomenon, common faults mostly occur between the wire and the wire terminal. After some wires are disconnected, the outer insulation layer and the wire terminals are intact, but the inner core wire of the wire and the wire terminals are disconnected. When judging, you can do a tensile test on the conductive wire and the wire terminal that is suspected of breaking. During the tensile test, if the wire insulation layer becomes thinner, it can be confirmed that the wire is broken.
The line is in poor contact, and the fault mostly occurs in the connector. When the fault occurs, it will cause the electrical equipment to not work normally. When judging, turn on the power of the electrical equipment, touch or pull the relevant connector of the electrical equipment, when touching a certain connector, the electrical equipment works suddenly and abnormally, indicating that the connector out of order.