How to resolve Volkswagen external lighting malfunction?

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When the bulb warning light illuminates in a Volkswagen vehicle, it typically indicates either a damaged bulb or a wiring issue in the lighting system. It is recommended to visit a service center for inspection and repair, and request them to reset the warning light if no issues are found. Below is relevant information: 1. Causes of malfunction: The bulb failure warning light is easily identifiable, usually represented by a bulb icon containing an exclamation mark. Apart from normal lifespan factors, lighting issues are generally related to bulb quality. Headlights are particularly vulnerable to water ingress - poor sealing can lead to moisture accumulation, which may cause filament burnout and reflector discoloration, ultimately affecting light projection. 2. Precautions: Vehicle lights should never be submerged. While water splashed during normal driving typically doesn't affect headlights, washing the engine bay with the hood open can easily lead to water intrusion. This occurs because the plastic mounting components are designed for dust prevention rather than waterproofing.