A little-known fact in automotive electrics and electronics is that the wiring harness in the vehicle is one of the heaviest and most expensive individual parts of a car (after the engine and transmission). In addition, the vast range of variants of today's vehicle models requires a tailor-made cable system for almost every possible configuration. Therefore, the cabling is largely manufactured by hand which makes it rather expensive.
The changes in vehicle electronics announced by the automotive industry will also result in massive changes in cabling: Introduction of a more centralized computer architecture with powerful domain computers instead of dozens of distributed ECUs; increased use of sensors with correspondingly higher data volumes within the vehicle and between the vehicle and the outside world, as well as the electrification of the drive train. It is precisely the latter factor that will significantly increase the amount of cabling in cars, explained Udo Hornfeck, Head of Research and Development at Leoni. The reason: electric vehicles require additional expensive high-voltage lines for AC-DC charging, high-voltage batteries and, traction as well as special wiring for the high-voltage battery and the battery management system. All these additional cables make the car more expensive. The fact that in return the combustion engine and thus the related wiring are omitted, does not make up for the price difference, the Leoni executive said.
Hornfeck explained that in addition to electrifying the drive system, driving automation and extended functionality in the comfort and infotainment areas would also contribute to rising prices. The reduction of the ECU number by the centralization of the computing resources, in contrast, will lead to less cable expenditure and therefore will have a price-reducing effect. The devices for automating driving have a relatively large share in this - for a car to automatically recognize the environment and adjust its driving strategy accordingly, significantly more sensors are required than in "normal" cars; in addition, data and power supply must be redundant, which also means more cabling. Some comfort functions - for example in the area of body control - have to be designed for high power peaks - this requires higher cable cross-sections and thus makes cabling more expensive, the R&D said.