xrsLT

Car: A4 B6 03'


My car has xenon headlights. But they work quite bad. At night I can barrely see the road. But if I turn the headlights off and on, xenon starts to shine way brighter for 5-10 seconds. Then slowly it get dimmer again. Off/on and they're brighter again. Those few seconds xenons light the road perfectly.
I replaced xenon bulbs and balasts with new ones, but the problem remained the same. I checked battery voltage while everything that drains electricity on. Voltage drops to 13.8V. That seem ok for me. What else can cause this problem? Photo taken with phone. It doesnt capture the reall difference of lighting.

1guitar

I can see the difference even though the pics were taken with a phone. I'm only guessing but there may be some kind of build-in electrical system that automatically lowers the current draw as I would guess that would be the reason the xenons work well for 5 or so seconds and once they start drawing their full current needs to maintain their bulb brightness the system is lowering their current draw by default. Electrical devices don't normally lower their current draw without the intervention of another electrical device that performs that function for them. Good luck.

D3Audi

What type of bulbs did you replace them with? Do not purchase cheap amazon/ebay bulbs. they have very cheap ballasts and bulbs and fail within a few days. purchase only high quality Osram or Phillips HID bulbs. they will cost you $150-$200, but will last a very long time. from your explanation, it sounds like a ballast issue, the ballast isn't regulating the power to the bulb properly. therefore an inconsistent brightness. When Xenon bulbs are turned on, the Audi will send a high voltage surge to ignite the ballast, then the ballast regulates the power from there on, thats why Xenon bulbs get super bright on start up, then dim, then slowly get brighter as they warm up to full brightness.

xrsLT

I replaced bulbs with OEM OSRAM D2S(they were'nt cheap at all ). Same is with balasts. Before that there was original balasts that came with the car from factory. Most likelly same thing with bulbs. And they behaved exactly the same as replacements. Thats why I doubt that it's balast issue. Have no ideas what even to check. Most obvious things (bulbs, balasts) are allready replaced.

D3Audi

Oh Jeez. how many miles are on the car? did you purchase the car with the bulbs working in the condition you stated? usually Xenon bulbs and ballasts are only good for 4-6 years or 50k-75k miles. some people tend to get more life out of them though. and some people push it right to the end, where it looks like the bulb isn't even on. I think that could have been what the previous owner of your car did. then you replaced them and they're a little brighter. thats a good sign. Xenon bulbs have a break in period of about 15-30 hours before they reach advertised brightness and color temp. your new headlight bulbs could be still breaking in. where did you purchase the bulbs? If breaking the headlights in is not the case, then it could be an issue with the car's electronics. not something you want to have to deal with because it would get expensive real fast. Do you have a code scanner (vagcom)?

xrsLT

Car mileage is ~180k. And yeas I purchased the car with bulbs that behaved the same. And one of the bulbs was flickering a bit. I replaced them several months ago so break in period should be over long time ago. Purchased them in a local store. Based on the price it shouldn't be fake china crap. First I purchased only bulbs, but few days latter on of the balasts died. So I had to replace them aswell. I dont have vagcom, but I can borrow it from a friend. Just I need to know what to check with it.

D3Audi

Look for any faults pertaining to the headlight/lighting systems of the car. The flickering doesn't sound good. Did it do that on start up, or while driving?

xrsLT

There's no faults at all. Checked that sevral times before. Flickering was while driving, when the bulb was allready worm. But I gues that was just bulb dying. No flickering with replacements.

D3Audi

Have you checked wiring to the bulb itself. maybe an animal chewed it or something. I'm not familiar with the B6 at all but I know other audi models from this generation are prone to developing shorts in the wiring harness, then it causes all sorts of funky xenon issues. have you checked fuses?

xrsLT

I replaced bulbs myself, so if there was any visual damage to wiring, I would have seen it. But there's nothing. Fuses shouldn't be the problem aswell. With fuses it either works or not.