Wire color code. In order to facilitate circuit identification and maintenance, wire color codes are usually marked on the terminals of the wires and on the circuit diagram. The International Standard Organization stipulates that the English letters of each color are used as the wire color code. my country, the United Kingdom, the United States, and Japan all use English letters, but some countries use their native language letters as the wire color code. The marking method of the two-color line in the automobile circuit diagram is that the main color is in front and the auxiliary color is in the back. For example, “B w” indicates that the main color of the wire is black and the secondary color is white. There is also a marking method of adding “/” or “one” between the main and auxiliary color codes.
In some car circuit diagrams, the cross-sectional area of the wire is also marked. For example, “1.5Y” means that the wire cross-sectional area of this line is 1.5mm2, and the wire color is yellow. For automobile wires with sleeves, the color of the wire sleeves is usually marked in the circuit diagram.