Wire Harness Detection Judgment
The harness provides the service equipment for a certain load source, such as trunk lines, switching devices, control systems, and so on. The basic research of the theory of traffic is to study the relationship between traffic volume, call loss and harness capacity. Harness is an important basic concept in traffic theory.
In order to facilitate the installation and maintenance, to ensure that electrical equipment can work in the most harsh conditions, the whole car electrical equipment used in different specifications, different colors of the wire through a reasonable arrangement, will be integrated, and insulated wire bundles Into a bundle, so that both complete and reliable.
2. Wire cross-sectional area and the color of the normal choice
1) the correct choice of wire cross-sectional area
The electrical equipment on the vehicle selects the cross-sectional area of the wire used according to the size of the load current. Long-term work of electrical equipment can choose the actual carrying capacity of 60% of the wire; short-term work of electrical equipment available current capacity of 60% -100% of the current.
2) wire color selection
In order to facilitate identification and maintenance, wire in the wire harness uses a different color.
In order to facilitate the call in the circuit diagram, the color of the wire are shown in letters, the representative of the color in the circuit map are notes.
Common faults in the car lines are: poor contact with the connector, short circuit between the wires, open circuit, ground and so on.
There are several reasons for the following reasons:
1) natural damage
Wire harness use more than the use of the period, so that the wire aging, insulation rupture, mechanical strength decreased significantly, causing short-circuit between the wires, open circuit, ground, etc., resulting in wire bundles burned.
2) Damage to the wiring harness due to failure of the electrical equipment
When the electrical equipment overload, short circuit, ground and other failures, may cause damage to the wiring harness.
3) human failure
Assembly or maintenance of auto parts, the metal objects will be crushed wire harness, so that the wiring harness insulation layer rupture; battery positive and negative lead wire reverse; overhaul circuit failure, random access, chaos cut wire harness wires, etc., can cause electrical The device is not working properly.
1) Detection and judgment of the failure of the wiring harness
In the circuit of the power supply system, which point of the ground, the wiring harness burned where the burned and intact parts of the junction, can be considered where the wire; if the wire harness burned to an electrical equipment wiring , Indicating that the electrical equipment is faulty.
2) between the lines of short circuit, open circuit, bad contact detection and judgment
- The wire harness is externally squeezed and impacted, causing damage to the wire insulation within the wire harness, resulting in a short circuit between the wires.
Judgment, you can open the electrical equipment and control switch at both ends of the wiring harness connector, with a meter or test light to detect the short circuit of the line.
- wire break fault, in addition to the obvious fracture phenomenon, the common faults occurred in the wire and the wire between the terminals. Some wires are broken, the outer insulation and wire terminals are intact, but the wire inside the wire and the wire terminals are open. Judgment, the cable can be suspected of breaking the wire and the wire terminal to do the tensile test, in the tensile test process, such as wire insulation layer gradually thinner, you can confirm the wire has been broken.
- bad line contact, the fault occurred in the connector. When a fault occurs, it can cause the electrical equipment to malfunction. Judgment, the electrical device connected to the power, touch or pull the electrical device related to the connector, when touching a connector, the electrical equipment work is normal, suddenly normal, indicating that the connector failure.