. General design of materials
 The general design of automobile wiring harness is based on the needs of subsequent vehicle expansion. It can adapt the same wiring harness to various models by reserving the loop and appropriately increasing the length of the harness branch, reducing the wiring harness material, avoiding waste of wiring harness design resources and reducing management costs.
 For example, the motor mirror signal loop is reserved in the instrument harness, left/right door harness, and left/right front wall harness. When a vehicle configuration changes from a manual rearview mirror to a power rearview mirror, it does not affect the wiring harness and directly borrows the original vehicle BOM. In a certain vehicle configuration, the double rear axle is replaced. Because of the different positions of the differential lock between the axles of the axles and the differential locks between the wheels, the branch of the chassis harness to connect the differential lock between the axles and the differential lock between the wheels is designed to be universal. Branching, using the same harness to match the configuration of different axles.
2, the universal design of the connector
 The connector is the key material on the harness and can cost about 60%. After the harness connector is universalized, it avoids repeated design verification, reduces the types of connectors, and reduces the types of crimping molds and conduction block modules. Bicycles can reduce design verification, procurement, and production management costs.
 The connectors are universal, not only the same connectors are used in the same model, but also the same connectors should be used in different models. For example, in a certain model, the inter-axle differential lock, the inter-wheel differential lock, and the under-vehicle start/stop switch connector are the same, and remain the same as the engine built-in in-cylinder brake, air filter blocking sensor, and the connector of the dryer. Type, so that the same terminal can be used even if it is not universal.