How to draw the automotive wiring harness diagram

Apr, 08, 2022 JKUN

Solution 1:

Here's how:

According to the vehicle wiring harness configuration schedule, the wiring harness direction in the 3D wiring diagram, the use of measurement tools in CATIA, according to the drawing requirements of the harness diagram, measure the required trunks, branches, snaps, cable ties, rubber parts and other dimensions, through reasonable design to arrange the 2D diagram, the outline of the harness diagram can be basically determined. As shown in the figure, the door wiring harness of an automobile manufacturer's SUV model is a 2D wiring harness converted from the 3 wiring diagram. Combined with the various technical documents provided by the main engine factory, determine the model, location and function of the sheath in the drawing, determine the model and schematic diagram of the cable ties, snaps, rubber parts, and improve the details of the drawing.


Solution 2:

In the process of automotive circuit design, in order to understand the actual situation of automotive electrical appliances in detail and facilitate the layout and connection of automotive circuits, engineers need to use block diagrams, automotive circuit diagrams and wiring diagrams. Although the line drawing reflects the actual installation position of the electrical equipment on the car, the wires on the diagram are crisscrossed, which increases the difficulty of reading the diagram, in order to make the circuit diagram closer to the reality, it is often necessary to draw the wiring harness installation diagram.

Harness diagram is based on the actual installation of electrical equipment on the car to draw the whole vehicle circuit diagram, mainly to the formation of the harness, the surface of the line less, the expression of the connection between the components has become its main content, in order to express the color of the clear wire, the terminal code of the joint, often need to be supplemented by harness grouping and terminal number table and harness terminal wiring table.


First, the composition of the wiring harness

The automotive wiring harness diagram is composed of multiple wiring harnesses, with main line harnesses and sub-wiring harnesses. The composition of each harness should be shown on the figure, how many branches there are on each harness, how many lines are on each branch, and what are the colors and stripes of the wires.


Second, the length of the wiring harness

The length of the harness includes the total length of the harness, the length of each branch, and the length of the interval between the two ends.


Third, the wiring code and wiring signs

The number of electrical appliances on the car is large and complex, in order to make the connection correct, each connection point should be marked with a wiring code and wiring signs to facilitate the connection.


Fourth, the plug

Since there are multiple wiring harnesses, wiring harnesses and wiring harnesses, branches and wiring harnesses, or branches and electrical appliances are connected through plugs, it should be indicated that there are several wires on each connector, where each wire is located in the connector terminal hole, what is the shape of the connector, and whether several adjacent connectors are easy to confuse.

In order to make everyone more aware of the division of the color of the wire on the car harness diagram, A few noun terms are introduced.

  • Primary      Color: The color with a large proportion of area in a two-color wire.

  • Secondary      color: A color with a small proportion of area in a two-color wire.

  • Monochrome      conductor: A wire with an insulating surface of one color.

  • Two-color      conductor: A wire with an insulating surface of two colors.

In drawing a car harness diagram, the color and code of the wires should be specified in the following table:

In this way, in the automotive wiring harness diagram, the color of the monochrome wire is composed of a color specified in the above table, and the color of the two-color wire is composed of two colors specified in the above table, and the selection of the color of the wire should be preferred to use monochrome, and then select two-color. Its color marking also has rules, all use color codes, if the monochrome wire, the color is red, marked as "R"; if the two-color wire, the first color is the main color, the second color is the auxiliary color, the main color is red, the auxiliary color is white, marked as "RW". In this way, the color of the automotive harness wire harness is clearly expressed on the harness diagram and is easy for designers to consult.

In addition, the iron wire of various automotive electrical appliances should be selected with black wire, and the black wire has no other use except for iron.

The cross-sectional area
of the wire is selected according to the size of the working current, for some electrical appliances with particularly small current, such as the indicator circuit, in order to ensure the due mechanical strength, the cross-sectional area of the wire shall not be less than 0.5mm2.

The cross-sectional area of the wire is marked in front of the color code, and the unit is not marked when the unit is millimeters, such as: 1.25R indicates the red wire with a cross-sectional area of 1.25mm2; 1.0G/Y indicates that the two-color wire with a cross-sectional area of 1.0 mm2 is green, and the auxiliary color is yellow.

One of the principles of automotive wiring harness drawing is simple and clear, so that the expression of all aspects of the entire diagram is close to reality, and it is more applicable to the use and maintenance personnel.