Basic Knowledge Of Automotive Wiring Harness Design

Taking the wiring harness of the whole vehicle as an example, the 0.5 gauge line is suitable for instrument lights, indicator lights, door lights, dome lights, etc.; the 0.75 gauge line is suitable for license plate lights, front and rear small lights, brake lights, etc.; Lights, etc.; 1.5 gauge wire is suitable for headlights, horns, etc.; main power wires such as generator armature wires, ground wires, etc. require 2.5 to 4 square millimeter wires. This only refers to the general car, the key depends on the maximum current value of the load, for example, the ground wire of the battery and the positive power wire are used separately for special automobile wires, and their wire diameters are relatively large, at least a dozen square millimeters Above, these "big mac" wires will not be woven into the main wiring harness.

Before arranging the wiring harness, it is necessary to draw a wiring harness diagram in advance. The wiring harness diagram is different from the circuit schematic diagram. The circuit schematic diagram is an image that expresses the relationship between various electrical parts. It does not reflect how the electrical parts are connected to each other, and is not affected by the size and shape of each electrical component and the distance between them. The wiring harness diagram must take into account the size and shape of each electrical component and the distance between them, and also reflect how the electrical components are connected to each other.

After the technicians in the wiring harness factory make the wiring harness board according to the wiring harness diagram, the workers cut and arrange the wires according to the regulations of the wiring board. The main wiring harness of the whole vehicle is generally divided into engine (ignition, EFI, power generation, starting), instrumentation, lighting, air conditioning, auxiliary electrical appliances, etc. There are main wiring harness and branch wiring harness. A vehicle main wiring harness has multiple branch wiring harnesses, just like tree trunks and tree branches. The main wiring harness of the whole vehicle often takes the instrument panel as the core part and extends forward and backward. Due to the length relationship or the convenience of assembly, the wiring harness of some cars is divided into the front wiring harness (including instrument, engine, headlight assembly, air conditioner, battery), the rear wiring harness (taillight assembly, license plate light, trunk light), roof Wiring harness (doors, dome lights, audio speakers), etc. Each end of the wire harness will be marked with numbers and letters to indicate the connection object of the wire. The operator can see that the mark can be correctly connected to the corresponding wire and electrical device, which is especially useful when repairing or replacing the wire harness.

At the same time, the color of the wire is divided into single-color wire and double-color wire, and the use of the color is also regulated, which is generally the standard set by the car factory. my country's industry standards only stipulate the main color, for example, it is stipulated that the single black color is used exclusively for the ground wire, and the red single color is used for the power line, which cannot be confused.

The wiring harness is wrapped with woven wire or plastic adhesive tape. For safety, processing and maintenance convenience, woven wire wrap has been eliminated, and now it is wrapped with adhesive plastic tape. The connection between the wire harness and the wire harness, between the wire harness and the electrical parts, adopts connectors or wire lugs. Connecting plug-in unit is made of plastics, and is divided into plug and socket. The wiring harness and the wiring harness are connected with a connector, and the connection between the wiring harness and the electrical parts is connected with a connector or a wire lug.