Xenon headlights are metal halide lamps that contain xenon gas. This gas amplifies the light produced from high intensity discharge electricity. Such headlights, while offering high levels of illumination, can develop problems.
Flickering xenon headlights, or headlights that go from dull to bright, can hamper a driver's visibility and create unsafe driving conditions. This problem often results from corroded wiring in the ballasts. Using electrical spray on the ballasts can correct a minor wiring problem. If the corrosion or damage is widespread, the wiring may require replacement.
Xenon headlights that operate only intermittently or unreliably can be the result of loose or old wiring, which can be replaced to correct the problem. If the wiring appears to be in good working order, the headlight may be faulty or near the end of its shelf life.
Many modern vehicles contain an auto-levelling system which adjusts the aim of xenon headlights automatically. A headlight aimed lower or higher than the other headlight is often a symptom of an auto-levelling issue. Most vehicles contain an adjustment device located behind the headlight which can be used to manually re-aim the headlight. If no such device is present, a certified mechanic should be consulted.