Hi. 2007 LS460 w/100,000 miles. Twice, in the last 3 days my drivers side low beam headlight has gone out on me. The first time, I noticed a flash, as if it popped, and thought damn, I need a new bulb. To my surprise, the next morning the light came on again, only to find it off when I reached my destination an hour later. The next two times I drove, it stayted on.

It's at the dealer now, and they're telling me that they've checked all the connections and tapped on the light to make sure it's not a bumping thing, but their opinion is that the headlight is "starting to go bad" and needs to be replaced. Now I admit, I don't know anything about these HID lights, but I see a filament in them, and my basic light bulb understanding is that the filament either breaks or it doesn't and the light either works, or it's shot for good. My suspicion is that the bulb isn't the problem and I don't want to pay $300 to replace it only to find out a couple of days later that it's something else.

Does anyone out there know anything about these bulbs. Could it really be that a bulb works sometimes and not others, or do I have a connection problem somewhere?

Thanks in advance

 

Sounds like you have a HID ballast or connectivity problem. If your HID bulb was to go out, it would not fire up at all. Also have you checked the fuse box for the headlamp? There could be a good chance the fuse is about to go or is burnt out.

 

with hid, i have seen a lot of cases where bulbs start to go out and come back and go out, and eventually dead. that has to do with how hid works, it's about using voltage to ignite power inside the bulb, not by filament. there is an exposed wire, that's the ground wire. in the middle of the glass tube you will see some powder, that's the sand

of course can't throw away chances of problems in ballasts, but most of the time it's bulbs. the easiest way is to swap the bulbs left and right and drive for a while, and see if the same bulb has problem or same side. that will tell you for sure

if you change bulbs, change both. otherwise color won't be the same on both sides. also, get the bulbs from ebay, much much cheaper, usually you are looking at 80-100 bucks max for a PAIR.

 

There is a very good explanation of HID technology here:

http://en.wikipedia.org/wiki/Headlamp

And that gets me to an amusing story about lens cleaners. When my car was new, and I didn't know what each button did and I was experimenting to find out, I was driving around one night and while stopped in traffic I decided to try that button on the dash that looks like a headlight/windshield wiper - because of age and poor lighting I couldn't really see what was on the button. I noticed it sort of made the reflections on the back of the car ahead of me twinkle. So, I went home and called my wife out to the garage to demonstrate the headlight twinkler. After the demonstration there were big puddles on the floor and my wash job was fouled.

 

Wow! You must have the best UPS truck out there! 100,000 miles in 3 years of actual usage is super ultra high. Are you on the road 23/7 or what?