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Discussion Starter · #1 ·
Hello all, I am new to this forum and also new to owning an Audi (purchased used two days ago for a second ‘fun to drive’ vehicle) and I really need some help from some of you gurus on this siteI This will be one of the first of MANY posts as I learn and work on this car. I have already searched the forum for prior answers (none were here) so this is my first post. As a background, I’m semi-mechancial (average simple stuff) and I am active in the local Jeep community (I do love my Jeep and doing ‘Jeep stuff’) and I am often answering questions in Jeep forums and doing the same thing in that community as most of you are doing here. I hope to learn about this new TT and be of value here as well since each vehicle was purchased for a different use.

CAR:

2008 TT Roadster convertible (8J), 95,000 miles, automatic 6-speed transmission, 2.0L 4cyl

CONTEXT:

I just purchased this (used) two days ago in order to use as a fun second vehicle which I intend to become my daily driver. As mentioned previously, I love my Jeep, BUT 14-15 mpg, the aerodynamics of a cinderblock, and an engine built for torque (not speed) isn’t ideal for a daily vehicle. That said, the prior owners of this TT weren’t ‘car people’ and there are some items that I need to repair, one is the headlights…

HEADLIGHTS ISSUE:

I am getting a ‘bulb out’ warning light and it iseems to be the driver side high beam. I took out both headlight assemblies (driver and passenger) and replaced both bulbs (with a new base) using 'Torchbeam D3S HID Headlight Bulbs, 6000K Diamond White, High/Low Beam” from Amazon (link here: Bulb Link). These are 35-watt Xenon bulbs that come with the base and they should be the same type of HID bulb with the metal stent base as the factory bulb. They were direct fits.

Buuuuut…. After changing both bulbs, here is the problem:
  • The bulbs/headlights shine at two very noticeable levels of brightness. The passenger side looks normal (dim setting) but the driver's side bulb is much brighter - as if it is stuck on bright while the passenger side is on dim.
  • When I switch the lights to 'bright' using the stalk on the steering column, the passenger's side light goes to bright but the driver's side is unchanged, it sets at the same brightness as it was already at (as if it is stuck on bright already???). It does not change from dim to bright or bright to dim - it just stays steady and pretty bright.
  • Also, when the lights are switched to bright, after about 10 seconds the passenger headlight (the only one that actually changes from dim to bright) automatically shuts off of bright and goes back to dim although the light switch on the steering column is still set to bright. It's as if it has a mind of its own. The driver side light just stays on at the same (and only) brightness it is already at. So, the passenger side won't stay on bright even when it's put there.
  • Finally, while driving, I noticed that the driver side light flickers off when I hit a bump as if there is a loose connection, however, I have checked and the connection for the plug is tight and in place and so is the connection to the bulb. I don't find anything loose.

WHAT I HAVE ALREADY TRIED:
  1. I replaced both headlight bulbs with brand new Xenon DS3 bulbs, so I don't think the bulb(s) is/are the issue. To be certain, I swapped bulbs between the two headlights and the problem stayed exatly the same with no change and it didn't follow the bulb, so it's not a bulb issue.
  2. I also swapped the headlight ballast between the two lights and again, the problem remained unchanged, so it doesn't seem to be a ballast issue either.
What am I not seeing here? Any suggestions or ideas from the group?
 

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You need to run a diagnostic scan with a vag aware tool such as VCDS. Or have someone do this for you. The error codes and messages will guide your next steps.
I think that car uses a shutter in the headlamp unit that lifts up for the main beam. Does that shutter work in both lamps?
 

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Discussion Starter · #3 ·
You need to run a diagnostic scan with a vag aware tool such as VCDS. Or have someone do this for you. The error codes and messages will guide your next steps.
I think that car uses a shutter in the headlamp unit that lifts up for the main beam. Does that shutter work in both lamps?
Thank you. I spent waaaay too much time troubleshooting this and finally took it into a shop that had more expensive garage toys (and expertise) than I do. They have told me that BOTH ballasts are bad and that the driver side headlight assembly needs replaced because there is something internal in that assembly that isn't working. Expensive. The ballast issue kind of doesn't make sense though because I physically swapped the ballasts from the driver to passenger side headlights (to check them) and the problem didn't follow the ballasts, the problem remain unchanged. So, I (in my shade tree mechanic way) thught I eliminated the ballasts as a cause and they're telling me they are the cause.

In any case, the ballasts in the car are model number 307 329 154 but the ONLY replacement ballasts I can find online ANYWHERE are 307 329 153 - are these interchangable or do you know?
 

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Discussion Starter · #5 ·
The ballast should have an Audi part number (printed on the side) similar this 8J0 907 391.
Thank you. I ordered one new (well, used) ballast from Ebay and when it arrives I'm going to test it on both lights and see if it 'fixes' either one of them. I plan on updating the post one way or another once I do in case others in the future have similar problems.
 

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You may want to buy a headlamp with ballast to replace your stuck high beam. I don’t believe there are serviceable parts inside and the unit is sealed so will need to be cut open.
good luck
 
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