Why Should Xenon Headlights Be Replaced After Several Years of Use?

[Austin]

Xenon headlights should be replaced after several years of use because significant light decay can easily lead to safety hazards if not addressed promptly. Method for Modifying Xenon Headlights: Disassemble the headlight cover from the base and remove the original sealant; install and secure the demon eye inside the lens, then install the angel eye and lens; adjust the horizontal alignment of the light beam, the parallelism of the focal points for high and low beams, and the wiring for the angel eye, demon eye, and dual-light motor; blow away dust inside the headlight cover, apply sealant, and reinstall the headlight. Components of Xenon Headlights: Lamp Head: No filament is used; instead, current is generated between electrodes to cause xenon molecules to collide and produce brightness; Electronic Ballast: Uses the 12V DC voltage from the battery to generate ignition high voltage for the lamp head; Wiring Control Box: Made of flame-retardant materials, it enhances current-carrying capacity by increasing the cross-sectional area of the power wires.

[VonKhloe]

Xenon headlights should be checked after five or six years of use. Last time I went for maintenance, the technician used a device to measure and said that if the light decay of old xenon bulbs exceeds 30%, they should be replaced. Although the bulbs haven’t completely failed, driving at night clearly feels less bright when reflecting road signs. What’s worse, when the bulb tubes blacken, the voltage requirement increases, causing the ballast to work under overload, which might eventually lead to replacing the entire set. Some headlights even shift from snow-white to bluish, making it hard to see the road in rainy conditions. Repair shops have seen too many cases where people tried to save money on bulbs but ended up burning out ballasts costing over 2,000 RMB. It’s recommended to check the brightness decay every two years—this is one expense you really shouldn’t skimp on.

[SanEmmett]

The actual lifespan of xenon headlights is much longer than halogen ones, but issues only become apparent after three or four years. My car started showing problems in the fourth year—it would flicker five or six times before lighting up, and the illumination turned grayish on rainy days. Upon removal, the electrode gap was noticeably larger, and the light spectrum had shifted. A mechanic friend mentioned that mercury deposition alters discharge characteristics, not only causing slow starts but also making the high-voltage coil prone to failure. This is especially critical for modified headlights—aftermarket ballasts paired with aging bulbs can lead to unstable voltage and sudden failures. When replacing bulbs, it's best to conduct a full system check to avoid repeated disassembly and wasted labor costs.

[OJasmine]

The most dangerous issue with aged xenon headlights is the flickering problem. Last week on the highway at night, the lights suddenly started flickering wildly between bright and dim, scaring me into pulling over at the nearest service area. The mechanic diagnosed it as unstable arc discharge due to aging bulbs. This kind of flickering is hard to notice from the driver's seat, but oncoming vehicles perceive it as aggressive high-beam flashing. Even more alarming, voltage fluctuations can damage the vehicle's computer systems—my neighbor's BCM module got fried this way. Now I make it a habit to test bulb resistance during every maintenance check. If it exceeds 3 megaohms, I replace them immediately rather than waiting for complete failure.