2015 Kia Cadenza Lighting Problems

The bulbs had originally been replaced in 2021 at the dealer. We took the car to the dealer November 26, 2024 having noticed how dim they were around May 2024. The dealer states no problem was found, lights appear to be working normally. These are HID lights. The DS1 bulb color is white, and the composite lens color is clear. The dealer has no idea what the problem could be. Called the xenon bulb manufacturer. They believe that with the bulbs only being 4 years old and the light being bright and even white(they're rated 5K) the problem is elsewhere in the electrical system. The dealer made a similar comment about their color when the car was checked. The dealer rechecked the lights 01/26/25, still could not identify a problem, and suggested that we start by replacing the bulbs, then move on from there. These bulbs retail for $400 and headlight assemblies run about $1700 ea. I advised that you cannot see much past the front of the car with the lights on and that either the high beams or fog lights need to be on when conditions dictate the use of the lights. It is nearly impossible to discern road hazards such as potholes or potential problems on the roadside within the headlamps arc.