HID Problem. Bad ballast or bulb?

[Denali]

This doesnt have to do with Bimmers but since everyone and their mothers here have em I figured someone would know.. My friends got a 98 envoy with factory HIDs. when they are turned on one bulb flickers a little.. gets very blue.. then purple.. then just flickers and shuts off.. but its not nearly as bright as it was before.. could this be a prob with the bulb or the ballast?

[Ryan Stewart]

I would guess bulb, the halides might not be generating the necessary pressure to vaporize the mercury. Its the one weakness of HID lamps. The more you start them the more of those halides you burn up and those are what "ignites" the bulb.

I would lean toward the bulb because it sounds like the ballasts are generating enough voltage to at least ignite something.

[Denali]

I was thinking that too.. just to add.. these bulbs are the older HID bulbs.. I think the d1r bulbs with the starter on the back.

[Ryan Stewart]

when the only problem could be on the bulb. The weak point of the ballast (with internal igniters) is the igniters themselves because they have to generate a bunch of 20k volt pulses to maintain an arc in the low pressure environment. The Xenon is under pressure and generates the very purple light while these pulses are trying to ignite the halides but every time you start the bulbs a little bit of these halides get burnt and dont work. Eventually there isnt enough to start them.

Physics is kewl!

[Denali]

hmm.. good to know.. now another question.. where the hell can I get one of these style bulbs?? I've got the same size in my jeep and need a spare too..

[waapples]

it's probably using the D2S bulbs.

check on ebay, they are hella cheap!

[djstattic]

D2R if it's a reflector housing... www.xenondepot.com is a great place to get rebased bulbs