wire harness fault detection judgment and replacement

1. Detection and judgment of electric wire bundle burnout failure

The burnt wire bundles are all suddenly occurring, and the burning speed is very fast. In the burned circuit, there is generally no safety device.

The rule of burnt out the electric wire bundle is: in the circuit of the power supply system, which point is grounded, where the electric wire bundle is burned, where the burnt and the intact part are at the junction, it can be considered that the electric wire is grounded; if the electric wire bundle burns out When the wiring to an electrical device indicates that the electrical device is faulty.

2. Detection and judgment of short circuit, open circuit and bad contact between lines the wire bundle are externally squeezed and impacted, causing damage to the wire insulation inside the wire bundle, causing a short circuit between the wires, causing some electrical equipment to lose control and the fuse to blow.

3. When judging, the electrical harness connector at both ends of the electrical equipment and the control switch can be disconnected, and the short circuit of the line can be detected by the electric meter or the test light.

In the case of a wire breakage failure, in addition to the obvious fracture phenomenon, common faults occur mostly between the wire and the wire terminal. After some wires are broken, the outer insulation layer and the wire terminals are intact, but the inner core wire and the wire terminal of the wire are broken. When judging, the tensile test can be performed on the conductive wire and the wire terminal of the suspected open circuit. During the tensile test, if the wire insulation layer is gradually tapered, the wire can be confirmed to be broken.

Poor line contact, faults occur in the connector. When a fault occurs, it may cause the electrical equipment to malfunction. When judging, the power of the electrical device is turned on, and the relevant connector of the electrical device is touched or pulled. When a connector is touched, the operation of the electrical device is normal and abnormal, indicating that the connector is abnormal. failure.

4, the replacement of the electronic harness assembly

1. Appearance inspection

1.1 The new electronic harness model should be the same as the original model. The wire terminals and the wires are connected reliably. You can pull the connectors and wires to loosen or fall off.

1.2 Compare the new electronic harness with the original electronic harness, such as the size of the electronic harness, the wire terminal connector, and the color of the wire. For any doubt, use a multimeter to test and confirm that the electronic harness is intact before it can be replaced.

2. Installation of electronic harness

The connectors, plugs, and sockets of each electrical device shall correspond to the sockets and plugs on the electronic harness. After connecting the connecting wires to the electrical equipment, leave a certain margin. The wires should not be pulled too tight or placed too loose.

3. Line inspection and connection test electronic harness

3.1 Line inspection: After the electronic harness is replaced, first check whether the connection between the electronic harness connector and the electrical equipment is correct and whether the positive and negative batteries are connected correctly.

3.2 Power-on test: The grounding wire of the battery can be temporarily disconnected. Use a 12V, 20W bulb to test the light. Connect the test light between the battery negative pole and the ground end of the frame, and turn off all the electricity on the vehicle. Device switch. The test light should not light when it is normal, otherwise, it indicates that the circuit is faulty. When the circuit is normal, remove the bulb, use a fuse with a capacity of 30A, connect it between the negative pole of the battery and the ground end of the frame, do not start the engine, connect the power supply of each electric equipment on the vehicle one by one, to the electrical equipment And line inspection, after confirming that the electrical equipment and the line are not faulty, remove the fuse and connect the battery ground wire.