A modular lighting system uses standardized, interchangeable components or light units so a vehicle manufacturer can configure functions, light patterns, mounting, and electrical connections for a specific application. The degree of modularity depends on the product platform and should not be assumed unless documented. Modularity can simplify vehicle design, product variants, assembly, service, and spare-parts management by reusing common interfaces. Different modules may provide driving, work, signal, or decorative functions within a coordinated installation. Designers must still confirm that every selected module meets the required optical performance, electrical interface, environmental rating, approvals, and mechanical constraints.