1) The new wire harness model should be consistent with the original model, wire terminal and wire connection is reliable, can be pulled by hand to pull the plug and wire with or without loose, off phenomenon.
2) The new wire harness and the original wire harness comparison, such as: wire harness size, wire terminal connector, wire color should be basically the same. There is doubt, the multimeter can be used to test, to confirm that the wire harness is intact, before replacement. 1) Inspection of wiring
After the replacement of the wire harness is completed, first check whether the connection between the wire harness plug and the electrical equipment is correct, and whether the positive and negative battery terminals are connected correctly.
2) Energized test
The battery hitch line can be temporarily not connected, with a 12V, 20W or so of the bulb to do the test light, the test light will be connected in series in the negative terminal of the battery and the frame of the hitch between the end of the car, close the car all the electrical equipment switch. Normal test light should not be bright, otherwise it shows that the circuit has a fault. When the circuit is normal, remove the bulb, with a capacity of 30A fuse, connected in series between the negative terminal of the battery and the frame hitch, do not start the engine, one by one, turn on the car power supply of the electrical equipment, electrical equipment and line inspection, in order to confirm that the electrical equipment and lines are not faulty, remove the fuse, connect the battery hitch line.
Wire harness wire commonly used specifications have a nominal cross-sectional area of 0.5, 0.75, 1.0, 1.5, 2.0, 2.5, 4.0, 6.0 and other square millimeters of wire, each of them have a permissible load current value, with the wires used for different power equipment. Taking the wiring harness of the whole car as an example, 0.5 specification wire is suitable for instrument lamps, indicator lamps, door lamps, roof lamps, etc.; 0.75 specification wire is suitable for license plate lamps, front and rear lamps, brake lamps, etc.; 1.0 specification wire is suitable for turn signal lamps, fog lamps, etc.; 1.5 specification wire is suitable for headlamps, horns, etc.; the main power line, such as generator armature wires, hitch wires, etc., require 2.5-4 square millimeters of wires. This just refers to the general car, the key to look at the maximum current value of the load, such as the battery hitch wire, positive power line is a special car wires alone, their wire diameter is relatively large, at least more than a dozen square millimeters, these "giant" wires will not be programmed into the main wiring harness.
Before arranging the wiring harness, you need to draw a wiring harness diagram, which is not the same as a circuit schematic. Circuit schematic is a representation of the relationship between the electrical parts of the image, it does not reflect how the electrical parts are connected to each other, not affected by the size and shape of the electrical components and the distance between them. A wiring harness diagram, on the other hand, must take into account the size and shape of the electrical components and the distance between them, and must also reflect how the electrical parts are connected to each other.
Wire harness factory technicians according to the wiring harness diagram made of wiring harness wiring board, the workers in accordance with the provisions of the wiring board to cut the line wiring. The main wiring harness of the whole car is generally divided into the engine (ignition, EFI, power generation, starting), instrumentation, lighting, air conditioning, auxiliary appliances and other parts of the main wiring harness and branch wiring harness. A whole vehicle main harness has a number of branch harnesses, just like the tree pole and tree branches. The main wiring harness of the whole vehicle often takes the instrument panel as the core part and extends front and back. Due to the length of the relationship or ease of assembly and other reasons, the wiring harness of some cars is divided into the front wiring harness (including instrumentation, engine, front light assembly, air conditioning, battery), the rear wiring harness (taillight assembly, license plate light, luggage compartment light), the roof wiring harness (doors, roof lights, audio speakers) and so on. Wiring harness on each end will be marked numbers and letters to indicate the connection object of the wire, the operator sees the sign can be properly connected to the corresponding wires and electrical devices, which is particularly useful in the repair or replacement of the wiring harness. At the same time, the color of the wire is divided into single-color wire and two-color wire, and the use of the color is also specified, usually by the car manufacturer's own standards. The Chinese industry standard only specifies the main color, for example, stipulating that single black color is exclusively used for the hitch wire, and red monochrome color is used for the power wire, which should not be confused.
Wire harness with woven wire or plastic sticky tape package, out of safety, processing and maintenance convenience, woven wire package has been eliminated, is now wrapped in sticky plastic tape. The connection between the wire harness and the wire harness, the connection between the wire harness and the electrical parts, the use of joint inserts or wire lugs. Plugs made of plastic, divided into plugs and sockets. The wire harness and the wire harness are connected to each other with the plug-in, and the connection between the wire harness and the electrical parts is made with the plug-in or wire lugs.