As an automotive wiring harness engineer or a professional working with wiring harnesses, here are some important things related to wiring harness expertise:

1. Basic electrical knowledge: Understand basic electrical concepts such as current, voltage, resistance, and power. Familiar with DC and AC circuit characteristics and calculation methods.

2. Wiring harness design principles: Master the basic principles and methods of wiring harness design. Understand the wiring harness layout, connection, assembly, and circuit diagram reading and understanding.

3. Electrical connectors: Familiar with different types of electrical connectors, including the selection, installation and maintenance of terminals, plugs, sockets and connectors. Understand the pin arrangement, insertion and withdrawal force of the connector.

4. Wire and wire selection: Understand the different types of wire and wire materials, including copper wire, aluminum wire and tinned wire. Familiar with wire specifications, current carrying capacity, resistance and current density.

5. Electrical protection and insulation: Understand the protection and insulation requirements of electrical systems, including the use of materials such as insulation bushing, insulation tape and insulation bushing to improve the safety and durability of wiring harnesses.

6.EMC (Electromagnetic Compatibility) design: Understand the basic principles and requirements of electromagnetic compatibility, including anti-interference design, electromagnetic shielding and ground design, etc., to reduce the impact of electromagnetic radiation and electromagnetic interference on the wire harness.

7. Wire harness test and verification: Master the methods and standards of wire harness test and verification, including connectivity test, durability test, insulation test and high temperature and humidity test.

8. Familiar with relevant standards and regulations: Understand the standards and regulatory requirements related to automotive wiring harnesses, such as ISO 6722, IPC/WHMA-A-620, etc.

9. Manufacturing process: Understand the process flow and method of wire harness manufacturing, including wire peeling, crimping, welding, marking and testing.