What are the causes of automatic headlight failure in the Audi Q5L?

[BenjaminAnn]

Audi Q5L automatic headlight failure can be caused by a faulty voltage regulator, excessive voltage, or poor contact in the battery cables. The causes of automatic headlight failure in the Audi Q5L include: Faulty voltage regulator, excessive voltage; Poor contact in the battery cables, leading to excessive no-load voltage from the generator; Short circuit between the generator armature and field coils. Burnt-out tail light filament, poor grounding of the tail light, or open circuit in the tail light wiring. Solutions: First, remove the tail light bulb and check if the filament is burnt out. If the filament is intact, use a test pen or screwdriver to scrape the tail light live wire terminal against the ground. If there is no spark, it indicates an open circuit in the tail light wiring; locate the open circuit and reconnect the wire. If there is a spark, it indicates poor grounding of the tail light.