In order to facilitate wiring, each wire end in the automobile wiring harness is welded with a terminal card, and an insulating tube is placed at the connection between the wire and the wiring. The terminal card that is often disassembled is generally an open type, and the terminal card that is less likely to be disassembled is often used. Shut up. Domestic new cars and foreign cars now use plug connectors, which is beneficial to the manufacture of cars and more conducive to maintenance. The plug connector is composed of two parts, a plug and a socket. wait. The plug pins are divided into flat ends and needles. When the connector is engaged, its guide grooves should be overlapped together first, so that the plug and socket are aligned and inserted with a little force, so that they can be connected together very firmly. The so-called guide groove of the connector refers to the convex and concave rails provided for the correct positioning of the connector when the connector is connected. A pair of plugs and sockets is generally impossible to insert wrongly due to the effect of guide grooves. Non-paired plugs and sockets will not be the same because of their number of pins and external shape, so it is impossible to insert wrongly. Therefore, it is very convenient and reliable to use the connector to connect the circuit.