ok i have a 06sti and the right side passenger hid seems to turn on when i start the car and then as soon as it heats up it flickers and then goes out.. now if i turn the car off then turn it right back on it will turn on and then a couple seconds later flicker then goes out.. i did this process a few times and it did this for a week. Now it wont turn back on at all... im trying to figure out if it is the bulb or the ballas or both?? i tried to look up some reasons why but couldnt find any so that is why i am posting this thread lol o and if you guys do know what is goin on here, what brand and size would you recomend i replace the bulb or ballas with? i called my local subaru dealer and they quoted me 185$ for just one bulb and i find that kinda steep for one bulb!! o by the way, is the bulb a H7 or D2S? sry noob question... thanks guys

D2s, and it sounds like you have a bad ballast. If you switch the bulbs and they work both sides its probably the bulb but if the bulb only works on one side its most likely the ballast. You can try swapping both to diagnose the issue, just don't touch the bulb(s)! GL let us know what you find.

It is probably more the ignitor that is the problem. But you can usually pick up a new or used ballast and ignitor as a set. Nissans and Infinitis use the same ballasts they are fairly common. You can get a new single one on EBay with the ignitor for like $85. Used they run about $50.

Any time something like this happens and the bulbs do strange things it is a good idea to change it out. Flickering, dimming, or shutting off can damage them. It is also a good idea to change HID bulbs in pairs since they turn bluer over time. It is called color shifting. If you just get one they won't match.

You can get Philips 85122 or 85122+ D2S bulbs on EBay for $75 a set. The 85122 are about 4100k when they are new but then color shift bluer over time to about 4300k. The 85122+ stay pretty close to 4100k over their life. Some have said they are a few hundred lumen brighter too, but I haven't seen any official tests.

fouron the floors guess seems correct.

swap some things around, and rule out the bad part.

if you end up needing an igniter cord, i have one available for sale.

ok i took out the bulb and it looks kinda burned out its got a smoky tint in core of the light... but would the ballas do that? i just dont want to buy a bulb and the ballas break it out.. you know.. well dope guys sounds good thanks for the tips!!!!!!! i will do some switchin around and see whats up!! i will let you guys know!!! thanks

ok i took out the bulb and it looks kinda burned out its got a smoky tint in core of the light... but would the ballas do that? i just dont want to buy a bulb and the ballas break it out.. you know.. well dope guys sounds good thanks for the tips!!!!!!! i will do some switchin around and see whats up!! i will let you guys know!!! thanks

To save you some time, it looks like its a blown bulb. If so, you should replace in pairs but they are EXPENSIVE. Check with your dealer if you have any sort of warranty left, they should cover it! GL let us know

Some slight haze and electrode erosion on older bulbs is normal. But as msesno said, get a new pair, not just one, both. If they are not still covered under warranty, don't get them from the dealer. They are super overpriced. Ebay is the way to go, just be careful. Get only the real Philips ones. If they are cheaper than $60 a set be leery. I picked up a set from there a few weeks ago for my Civic's retrofitted headlights.

If that doesn't take care of the problem pick up a new ballast.

i took both the bulbs out and switched them around and it seems to be the bulb!!! but you are definitely right about switching them out in pairs for new ones!! thanks guys!! now on to trying to disable my day time running lights!!!! lol