What color abbreviation represents a black wire on a European vehicle wiring schematic?

The correct representation of a black wire on a European vehicle wiring schematic is indicated by the abbreviation 'BK.'

In wiring schematics, colors are commonly represented by standardized abbreviations to provide clarity and uniformity in identification. The use of 'BK' for black is consistent with many technical references, making it easier for professionals to understand and follow wiring diagrams without confusion.

The other choices represent different colors or conventions; for example, 'GN' typically stands for green, 'SW' could represent a specific shading or a different color, and 'BL' is often used for blue. This standardization is crucial for automotive technicians to ensure accurate connections and troubleshooting in vehicle electrical systems.