I have a question concerning when to change the Xenon / HID bulb. I have a '99 GS400 with the original bulbs. The car is about 5 yrs oId. I find that sometimes the light does not seem as bright at night as it used to when the car was new. Not sure if it's me or the lights. From keeping corals and their need for intense light, I know that Metal Halide bulbs shift in color temperature as well as the amount of light (lumens) that they output. Thus, I am wondering if this is also true of HID / Xenon lamps. If so, is it time to replace the existing bulbs even though they still work. Also, where should I get the replacements from ?? Dealer or aftermaket parts place ?? Where can I find instructions on changing them since the lights are also auto-leveling ?? Any info will be greatly appreciated.

 

well it should be the case that suddenly one light become very blue. that's the time to change

 

Automotive xenon lamps contain metal halides, and thus are prone to the same bluing/dimming as commercial metal halide lamps.

Here's a page with a description of the fill mix inside a D2R capsule:

http://members.misty.com/don/d2.html