What is a headlamp bulb?
A vehicle's headlights (or headlamps) serve to illuminate the road during nighttime driving and to make the vehicle more visible during daytime driving. The headlamp system includes a low beam used for normal driving, and a high beam that is only to be used when no other cars are present on the road. While cars of the past relied on round, sealed-beam lamps, modern vehicles feature headlamps with aerodynamic shapes and replaceable halogen bulbs. Some headlamps are powered with high intensity discharge (HID) bulbs that put out more light. These lamps are also known as "Xenon headlamps" and stand out by their bright bluish-white glow.
How does the headlamp bulb work?
A headlamp incorporates a bulb placed in front of a reflector (or a series of mirrors) that projects a beam of light through a lens and directs the beam to the road ahead. Halogen lamps produce more light with less heat output than older incandescent bulbs due to the halogen gas injected into the bulb. HID, or “Xenon,” headlamps provide even more light by producing an electrical arc for illumination rather than a glowing tungsten filament. Some late model vehicles feature self-leveling headlamps that that remain level with the road regardless of the angle of the vehicle. Vehicles with "adaptive headlamps" use a motor to shift the focus of the lamp to follow curves in the road.
What are the symptoms related to a bad headlamp bulb?
The most common symptom of a headlight bulb that needs to be replaced is a lamp that does not work. Some headlight bulbs will work intermittently when they are wearing out.
Can I drive with a headlamp bulb problem?
While it is possible to drive a vehicle with a burned out headlamp bulb, it is not legal in most states, and in others a burned out headlamp bulb is considered an equipment malfunction. Care should be exercised when driving with a burned out headlamp, as the lights serve not only to illuminate the road, but also to signal drivers to oncoming traffic. A burned out headlamp bulb should be replaced as soon as possible.
How often do headlamp bulbs need to be replaced?
The lifespan of a headlight bulb depends on how often the lights are used, how roughly the vehicle is driven, and how the bulb was handled on installation. A standard halogen headlight bulb can last as long as one thousand hours of operation, and a high intensity discharge (HID or "Xenon") bulb can last twice as long. Since headlight bulbs may contain sensitive filaments, rough driving or frequent driving over rough roads can cause the bulbs to wear out faster. Also, oil from a technician's hand during installation can create hot spots on a headlight bulb, which causes the bulb to burn out faster.
That is known as a “dipped headlight” and this post is written to help you troubleshoot and fix it.
The truth is that even Audi dealerships are notoriously bad at fixing this problem.
Their remedy is typically to suggest replacing the bulbs and ballasts at full retail price, costing you several thousand dollars for a job that is something you could fix yourself for a tenth of the price.
After reading all of my favorite Audi forums, I found a host of information, some of it helpful, some of it conflicting, and some if it misguided. But piecing together the consistent recommendations as well as a little educated guessing and fact checking, I’ve figured out a good approach for anyone who gets this problem in their 2002-2008 Audi A4, S4 or RS4 and wants to try to fix it themselves. The steps listed here will probably also work for other Audis as well, although may differ somewhat.
Since originally posting this I’ve gotten hundreds of comments (literally) with others experiencing this issue on a variety of Audis.
Unfortunately, the dipped headlight warning appears to be a super common issue, and can also point to any number of issues with your headlights.
I’ve also updated this post with revised ideas to help you fix the problem easier, after years of helping others I’ve refined my approach.
First of all, what does “Dipped Headlight” even mean?
Simply put, “Dipped Headlight” is Audi-speak for “there is something wrong with your low beam headlight” and can mean a number of things.
This is part of why it is so difficult to troubleshoot and fix on your own, as the error doesn’t give you much information about what the problem is.
If you have a VAG-COM cable, or know someone who does, the cable can read your car’s computer and tell you the exact error code which will help tremendously. For some people this error message only comes on intermittently, such as when they’re driving slow, when the car first starts up, or in cold weather – for others, it comes on every time.
You can also pickup a cheaper OBD2 scanner on Amazon which can read codes and at least give you a specific error code and message to troubleshoot, like this one for $23.
Regardless this error light is a catch-all warning and therefore not very helpful – which is why this issue is so frustrating to have.
Typically there are several major culprits:
- Bad headlight bulbs – the bulb has gone bad, but isn’t completely out.
- Bad xenon ballasts – the ballast has started to malfunction, causing the error and likely harming your bulbs too
- Bad wiring in the headlight or xenon motor – the wiring and modules within the headlight is somehow damaged
- Bad ride height sensor or calibration – if the car can’t sense the right height level of the car, this will trigger an error
What to Check First
There are several things that most commonly cause this error after reading dozens of owners messages on Audizine, Fourtitude, Audiforums and other message boards. I’ve listed them below in the order of how’d I’d recommend checking and testing the problem.
It seems the most common issue is that a ballast has gone bad…the bad ballast then causes damage to the headlight bulb, requiring you to change the bulb too. If you only change one or the other, you do run the risk that you’ll have to replace it again due to damage that occurred.
If you are getting this issue only on one side, i.e. Dipped Headlight Left or Dipped Headlight Right, then this is a big clue for troubleshooting.
To isolate if it is the headlight bulbs, ballasts, or something internal in the headlight itself, simply swap both the bulbs and ballasts from left to right headlight. If the dipped headlight error on your dash changes from “Dipped Headlight Left” to “Dipped Headlight Right” (or vice versa) then you know that the issue lies in either the bulb or ballasts.
If this is the case, you should order one new bulb and one new ballast (using the links in this post) and replace the bad side and you should be good.
I strongly recommend changing both bulbs and ballasts – even if only the ballasts were faulty, the bulbs likely suffered damage from the bad ballasts and will need replaced soon, and replacing bulbs requires the bumper to come off so its best to do this all at once. It also eliminates all possible sources of the dipped headlight error, as this can be a tricky problem to resolve and it’s better to be aggressive on the treatment of it.
If the problem isn’t isolated to one side or another, and the above trick didn’t work, then you’ll need to troubleshoot the problem one by one in the order listed below:
Headlight Bulbs
Typically the best place to start is new headlight bulbs, as they are often the culprit and one of the cheapest and easiest things to fix – even if new headlight bulbs don’t fix the problem, you’ll eventually need to replace them anyway, so consider it preventative maintenance.
If you get the “headlight bulb out” message, see your headlights “flicker” on/off occasionally, or notice that your dipped headlight error only comes on in cold weather or at first start up, it’s likely your headlight bulbs may be on their way out.
Follow this DIY for tips on picking the right bulbs and how to install them: //www.nickscarblog.com/diy/replacement-d1s-headlight-bulbs-for-b7-audi-a4s4rs4
Headlight Ballasts
The ballasts are also known to fail, which can cause this issue – even worse, the failed ballast burns through bulbs, so if you’ve had a bad ballast for a while then you’ll need new bulbs too. Rumor has it some ballasts have been recalled by Audi, in which case you can check with your dealer to see if your car qualifies for the recall, in which case the service and replacement should be free – problem solved! However, if you’re not covered by recall and your ballasts are indeed bad, then you have a few options:
- Have your Ballasts Rebuilt – Contact Phil at tbm850 @ gmail.com – he can rebuild your factory ballasts to fix whatever is wrong, and actually strengthen them so it doesn’t happen again. He only charges $170 per pair for this and can turn it around in about a day then overnight ship it back, so you’re downtime is minimal. I’ve worked with Phil before and he knows the B7 Audi headlights better than pretty much anyone out there, and he’s an airplane mechanic so it’s a professional job.
- Buy New OEM ballasts – the ballasts are shared by a lot of manufacturers, so don’t order through Audi. You can pick up the ballasts on Amazon for about $110 a piece:
B6 Ballasts (2002-2005)
B7 Ballasts (2005.5-2008) WITHOUT AFS:
B7 Ballasts (2005.5-2008) WITH AFS: //www.ecstuning.com/b-magneti-marelli-parts/xenon-bulb-ballast-priced-each/8p0907391~mm/
Either way, I strongly recommend new bulbs if you had a bad ballast, as that bad ballast likely caused premature wear on the bulbs and they’re likely to burn out soon – best to replace both while you already have the headlights off the car!
This is also a great time to do the clear corner mod, LED DRLs, and/or LED City Lights since you’ll have the headlights off the car anyway…
Auto Leveling Sensor
If you recently lowered your car, or hit a really hard bump to your drivers side front or rear wheel, this could be the problem. For cars equipped with auto-levelling sensors, the sensors themselves are located in the wheel wheels near the lower control arms so they can adjust the headlight aiming based on the suspension load. For some people when they lower their car, the sensor is out of range as the suspension has been altered. For others, a hard bump to the front wheel could potentially break the sensor or cause it to become unplugged. To access the sensor, take off your drivers side front wheel and look near the bottom of the suspension. The sensor bridges the lower control arm to the body and looks like this:
If it is damaged or the wires have frayed, you can order a new one here: //www.ecstuning.com/Audi-B6_S4–V8/Lighting/Headlights/Leveling/ES440960/. If you are lowered, you may just need to bend the upper part of the bracket so the top of the sensor is higher again. Once you have inspected and either repaired or replaced the sensor, you will need to recalibrate it using vag-com. Follow this DIY for instructions on how to do that: //www.a4mods.com/index.php?page=webcontent/pages/autolevel.html&category=6
Headlight Swivel Module
This is the issue I had after replacing the bulbs and ruling out that issue. It turns out that while I was replacing my DRL bulbs, I must have knocked the main headlight swivel out of place, preventing the headlights from being able to aim correctly. The swivel is VERY sensitive, so if you’ve been in accident, or were tinkering inside of your headlights too aggressively, it’s possible you broke a swivel arm or knocked it out of alignment. Looking closely at the headlight I could see the projector lens on my driver side was pushed forward and not aligned the same way my passenger side was, so I reached inside the headlight housing (much the same way I did when replacing the bulbs) and pulled the projector lens “back” away from the front of the housing until it clicked back into place. I then recalibrated the headlight adjustment using the DIY on A4mods and cleared the codes and the problem went away: //www.a4mods.com/index.php?page=webcontent/pages/autolevel.html&category=6
If you run the vag-com on your Xenons and find error code 02769 or 02770, it is likely your projector lenses are out of alignment and you may be able to manually push or pull them back into place. It is also possible the motor inside the headlight has malfunctioned or stopped working altogether, in which case you’ll need to buy an entire new headlight housing – like mentioned earlier, eBay is your best bet for that, and expect to pay about $200-300. But hopefully you may just be like me and have to massage the projector lens back into place and reset the headlight adjustment via VAG-com and the problem will go away 🙂
VAG-com adjustments (reset to factory spec)
If you change anything other than the bulb, you may also need to recalibrate your headlights and reset the adjustments to factory. To do this, follow the A4mods.com DIY mentioned earlier. For me, I fixed the projector lens being knocked out of place then recalibrated the headlight adjustments using VAG-com to fix my errors.
The last resort is to pull Fuse #10 if you have adaptive or auto-leveling headlights – this disables the feature entirely, which should also disable the warning light. This isn’t the best way to fix it as your headlights might be out of alignment still, and you lose the adaptive features, but hey – at least it gets rid of that pesky warning light and beeping 🙂
The Last Resort – Replace the Whole Darn Thing
At a certain point, you may be better off replacing the entire headlight assembly as you can usually find complete headlights (including ballasts and bulbs) used on eBay for a reasonable price.
This also covers you in case the problem lies elsewhere in the headlight housing, and since you’re going through the trouble of removing your headlights this is probably worth the extra $100 over the cost of a ballast to not have to remove all of these parts more than once.
If your car is older, chances are it’s pretty easy to find used headlight assemblies on eBay from wrecked cars that work just fine, and they’re usually pretty cheap, or you can pick up a new set on Amazon here:
Make sure you have the right part number prior to ordering – the part number can be found on a white sticker on top of your headlights which you can see simply by opening the hood – compare this to the eBay listing to confirm you’re swapping “apples to apples” with the replacement housing. The biggest thing to watch out for is AFS vs non-AFS, as you can’t mix these up. AFS is Audi’s “curve lighting” system which has its own wiring to power this motor, and switching between them is not easy to do.
To swap out the headlight housings, follow this DIY: //www.audizine.com/forum/showthread.php/234131-B7-A4-S4-Clear-Corner-Mod-Removal-of-Bumper
Still stumped? Leave a comment, I’ll do my best to help…