Halogen to Xenon Conversion for B7 Audi A4s (2005.5-2008)

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I’ve been asked how I did this conversion on my B7 Audi A4 in the past, so I’m finally getting around to writing it up in typical Nick’s Car Blog fashion to share with inquiring minds. It’s a great mod and while I won’t attempt to recreate step-by-step instructions, I’ll go into deep detail as to what you need, why you’ d want to do this mod, and where to find instructions once you’ve accumulated all of the parts…Above you can see my former A4 before and after the conversion, with the picture on top featuring the OEM bi-xenon headlight housings.

OEM Xenons versus Aftermarket Kits

The biggest consideration that you need to determine first is do you want to go the OEM route, or do you want to consider aftermarket options? It will probably suprise no one that has read this blog here that I highly recommend the OEM route, but it’s at least worth mentioning your other options. The only downside to the OEM route is that it is the most expensive option, but in terms of functionality, output and aesthetics, it’s you’re best option. Here are your primary options:

OEM Bi-Xenon Headlight Housings, Ballasts & Bulbs


The highest quality option, and one that will look great and work great for years to come. They also will help improve resale value of your car, and after the conversion it will be nearly impossible for anyone to tell your car ever had halogens in the first place. Pictured above are my OEM bi-xenons I retrofitted to my A4, which were E-Codes I sourced from Germany.

Aftermarket Headlight Housings, Ballasts & Bulbs


This is probably your second best option, because the aftermarket headlight housings have projectors to focus the xenon beams so that you’re not blinding oncoming traffic, as opposed to drop-in kits. The downside is that the options out there, primarily manufactured by Depo, are of lesser quality and are immediately recognizable as aftermarket. Many of the options include LED running lights to look more like the modern style Audis (B8 models or R8s, to be more specific) but often come out looking a little cheap and also tend to have problems with the LEDs burning out.

Drop-In HID Kits

HIDs with or without a Projector

The advantage of this route is that you’ll only spend about $50 for the HID “kit” that includes ballasts and bulbs, but the downside is that your headlight housings lack projectors so the HID lights will be blinding to everyone in sight. I’ve done this in the past and although you can definitely see better while driving, it looks pretty terrible to everyone around you and doesn’t really belong on an expensive German car. I recommend this route for the fog lights as they’re positioned low enough on the car not to bother anyone, but I do not recommend this for your driving lights as it’s a safety issue. For a good read on what a projector is and what it does, check out this thread on Reddit – which also deserves photo credit for the image above.

Retrofitting projectors to your halogen housings, then using a drop-in HID kit

This has been done before, but it takes extreme DIY savvy to do. Audizine headlight expert “fly300kts” has retrofitted Acura and Subaru projectors into halogen housings, and it actually creates an even higher quality cut-off than the OEM Audi projectors do, but this is a very technical and tedious DIY that isn’t for the faint of heart – and if you do it wrong, could end up falling apart. If you’re brave and savvy, this could be a legitimate option for you, but won’t be for most…

OEM Conversion: What You Need to Buy (And How Much It Costs)

OEM Bi-Xenons

Okay let’s assume at this point you would like to go the OEM route – what’s it going to set you back? The OEM headlights are insanely expensive when purchased through a dealership – expect to pay $900-1200 per side, and that doesn’t even include the ballasts and misc. parts you’ll need. No thanks! Instead, you’re best method here is finding lightly used headlights on eBay or the Audizine classifieds and retrofitting to your car – they can be found quite easily off of wrecked cars in sets or singles, and be had for much cheaper. In general, expect to pay between $500-800 for a complete set of OEM bi-xenon headlights with bulbs and ballasts depending on condition and how eager the seller is. Check out these eBay listings for a good start, then cruise over to the Audizine Classifieds to see if any sets are available.

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Note that there are a few options when selecting a set of OEM bi-xenon headlights:

  1. US versus European Market headlights – these differ in that they have chrome inserts rather than dull grey, and often also have clear turn signal lenses rather than amber (although some markets in the EU still use amber, so amber does not necessarily mean they are US spec). 
  2. With or Without AFS – AFS stands for automatic leveling & focusing system, and is the feature where the projectors dynamically adjust and turn when your car turns to illuminate the road ahead of curves and maneuvers. It’s a great feature, but not necessary if all you want is HID lighting. Note: Auto-leveling and AFS are two different things. Auto-leveling is equipped on all xenon lights, and only controls up/down leveling. AFS is adaptive and goes left/right and is more sophisticated than simply auto-leveling, so do not assume these are the same thing.

OEM Xenon Headlight Part Numbers:

  • US with AFS: 8E0941029BD (L) and 8E0941030BD (R)
  • US w/o AFS:  8E0941029BA (L) and 8E0941030BA (R)
  • EU with AFS: 8E0941029BP (L) and 8E09410030BP (R)
  • EU w/o AFS: 8E0941029BM (L) and 8E0941030BM (R)

Secondly, you’ll need an adapter harness. Kufatec makes a great harness that is literally plug-and-play for all of your needs. This will make sure the new headlight housings get the right amount of power for the ballasts. It is not necessary to replace anything else, such as the headlight switch, for this mod. This harness costs slightly over $100 and can be found on the Kufatec website.

OEM Xenon Bulb Guide:


Since the headlights will be off your car, this is by far the easiest time to install LED lights and resistors in the DIYs above. You can also black out your headlight housings or install RS4 grille easily at this time since your bumper will be coming off anyway.

All in all, expect to pay around $800 for the headlights and wiring adapter, give or take about $100…

Installing OEM Xenons on Halogen Equipped Cars

Okay so you’ve got all of the parts, and your headlights are ready to get installed – now what? Here comes the fun part…

Step 1 – Remove the bumper and headlights

This is the “easy” part, more or less…and something you’ll need to get used to when owning a B7, as it’s required for a lot of things. Follow this guide: 

Step 2 – Install New Headlights & Wiring adapter

This part is pretty tedious, as you have to snake the wiring adapter through the firewall and into the cockpit, then splice it into your headlight knob in the interior…this isn’t technically challenging, just a little tedious. There are two guides to do this – on my A4 I followed the Audiworld one, but the Audizine one was written more recently and is very detailed. I’d suggest reading both…

Step 3 – Use VAG-COM To Update Settings

Last but not least, you have to update your car’s computer so it knows you have xenons and not halogens anymore. This is a simple coding change, but requires using a VAG-COM cable so you’ll either need to buy one, borrow one, or find a shop nearby that will do this for you. Once you have access to a cable, it should only take 5 minutes to change. To adjust follow these instructions (and always write down your original settings first, just in case):

Go to Components – Module 9 and change the fourth digit to either a 2 (with Daytime Running Lights) or a 3 (without DRL). For example if the code reads xxx?x, update the ? to a 2 or 3 (it is likely a 0 or 1 currently, which are for halogen cars). Additional documentation on VAG-COM coding of headlights can be found on the Rosstech website.

In Summary:


I definitely recommend going the OEM route if you’re looking to add HIDs to your halogen equipped A4 or S4. Expect to spend between $600-1000 to get a complete set of headlights and the wiring adapter, which is somewhat pricey, but remember it will improve the resale value of your car…not to mention the safety benefits. The installation requires removing the bumper, installing the wiring adapter, and updating your ECU via VAG-com, but is certainly DIYable. Many have done this in the past (myself included) and can help walk you through it if you run into issues. Expect to spend 2-3 hours completing this mod depending on how experienced you are with removing the bumper.

Nick Roshon

Nick has been an Audi owner and fanatic for the last 10 years, and started Nick's Car Blog in 2009 to share DIYs and pictures of his A4. Currently he drives a 2012 Audi TT-RS, and has previously owned a B7 S4, B7 A4, and an 82 Audi Coupe (GT) LeMons race car. In his day job, Nick is a digital marketer and lives in San Diego, CA, USA.


  1. Glad you posted this, I’ve been debating whether to get the B8 style vs the OEM Xenons.

    The b8 look alike really go out a lot?

  2. wow great write up nick. unfortunately i’ve always been one to cut corners and aftermarket is obviously cheaper,usually brand new and gives me the look i really wanted but as with anything you always get what you pay for and I’ve noticed that the fitment is usually a little off as well.

  3. @Mike – I think it depends, the headlights themselves work well I’ve just heard the LED strips in them to give the B8 look tend to go bad on some brands and makes, although difficult to tell if it those are one-off problems or more systematic.

  4. Hey Nick – I’ve a 2007 RS4 and recently changed the stock bulbs for headlights, fogs and DLRs to 6000K bulbs and have been getting error codes (bulbs out) for all these bulbs. Do you happen to have some insight on this? Thanks and appreciate your help!

  5. I had a guy order online so will get the information from him. The beeping goes away if I turn on the light switch and drive for a few minutes but the error codes continue to display on the tachometer. What’s strange is that if I leave the headlight switch in off position, the beeping stays on no matter how long I drive, which is quite annoying.

  6. I had a guy order online so will get the information from him. The beeping goes away if I turn on the light switch and drive for a few minutes but the error codes continue to display on the tachometer. What’s strange is that if I leave the headlight switch in off position, the beeping stays on no matter how long I drive, which is quite annoying.

  7. My friend is in need of switching out his halogens and would like OEM projectors like you have listed. If he ordered those you have listed above what else would he need. Its the second listing down and doesn’t look like they come with bulbs or ballast so I am assuming he would need a drop in kit.

  8. Its actually the last one down now. Its the listing with the pair of projectors for 467.50

  9. It doesn’t appear that comes with bulb or ballasts – he can reuse the turn signals but you’ll need main headlight bulbs, ballasts, the wiring adapter, and he may need new DRLs and City Lights but I can’t remember on that…

  10. Hi Nicks great DIY . I plan on going the OEM xenon route the cheapeast i could find is ebay Xenon replacement headlights for $500ish but doesnt include ballast or bulbs now i wanted to get a 8000k hid colour bulb anyway do you know what ballast and bulbs i would need to purchase seperatly??? trying to keep the cost as low as possible

  11. Im looking to do the same thing to my facelift b8 A4. is this going to be more or less the same process with a few different tweaks? IE in harnesses and programming

  12. i have a confusion, i have my car with part number 8e0941004bm. i need to change because, its brokern. What is the diference with the part number 8E0941030BM or 8E0941029BM or 8e0941003bm. Are not the same??

  13. 8E0941030BM vs 8E0941029BM – Passenger side (L) vs Drivers side (R), Xenon
    8e0941004bm vs 8e0941003bm – Passenger side (L) vs Drivers side (R), Halogen

    Whenever you see a one digit difference between two parts, it’s often just left versus right side, FWIW.

    Hope that helps!

  14. Any experience of the car not accepting the new coding. I tried to fit my oe bi xenons and couldnt get the coding to change to either 00021 or 00031. It would change any of the other numbers just not any of those. This is on a European b7.

  15. Quick and dirty after-market HID upgrades?… Only in America!

    In Australia, you essentially need to replicate the ENTIRE HID system, which includes the headlight washers, which are usually built into the front bar. It appears these requirements follow European mandated standards.

    Once you include the headlight cluster, ballast, HID-compatible front bar with washers, and, painting the bar, the cost comes close to $2 000. A cheaper option is to use a complete used kit, from a wrecked A4 example, but, you probably need to paint the front bar – even if it’s the same factory colour – so it blends in with the rest of the car.

    If you skirt the law with an illegal HID kit, and the you are pulled over by the police at night, the officers will pick up pretty quickly that the bright white headlights are amiss. The vehicle will be declared defected, you pay a fine, and, you might be instructed to have the car towed away for the eventual repair. A lousy outcome any way you look at it.

    In Australia, the B7 3.0L TDI (diesel) S Line quattro had HIDs standard. I think. As in Europe, the TDI was top of the range for the A4 – save for the rarer S4 and exotic RS4 – of course.

  16. Stephen – that is interesting, but the upgrade above is all OEM and I don’t see why you’d need to swap out the front bar and washers…you would just need to update your VAG-com coding from AU settings to ROW or US to indicate you have xenon but no headlight washers, and it should work…just my 2c.

  17. Thanks, for the reply, Nick.

    In a sentence: different countries, different laws.

    All commonly sold new vehicles in Australia must be compliant with the current Australian Design Rules (ADR). In fact, every vehicle must have a Compliance Plate confirming this, before it can be sold and delivered to the consumer. In practice, however, the consumer does not need to concern him/herself with this requirement, as the vehicle manufacturer completes this task.

    An extreme example of this is when an Australian wants to privately import an American Chevrolet Corvette or Ford F-150, a rigorous, arduous and for most people – prohibitively expensive – ADR compliance conversion process must be completed before it can be driven. I remember reading once that even the original sun visor on an American vehicle did not meet the ADR.

    Any way, getting back to HID Xenon retrofit legalities, the ENTIRE system – including HID-compatible front bar with washers – must replicate an equivalent Audi A4 which had HID Xenon installed at the German factory. Similar laws apply to the UK. Again, when the B7 sedan was new in Australia, it appears only the 3.0 L quattro TDI had HID Xenon standard.

    As for your old silver B7 you sold in 2012, a similar B7 would be illegal to drive in Australia as, as you guessed, it lacks the all-important headlight washers, built into the front bar.

    Have you ever noticed that when Audi HQ in Germany release official publicity photos of A4s, the HID Xenon-equipped examples always have headlight washers?

    This British investigative journalism piece succinctly explains the state of affairs:

    In the end, for informed and law-abiding Audi A4 drivers in Australia and in the UK, for the most part, do not bother with HID Xenon retrofits as it is too complex and costly.

    You Americans have it easier.

  18. Nick i tried everything but my xenon headlights still don’t turn on on mi audi 2008 a4 do you know anybody who can take a look in mi car in San Diego area and see what’s wrong?

  19. Hi Nick,

    So I bought Eagle Eye DRL (below link) for my 2007 Audi A4 B7 (H9 instead of H7 bulbs). The DRL aren’t as bright as I wished they were (close to OEM level is what I hoped for) and I’m not really liking the projector output even after I had an H9 Morimoto HID kit installed. They are bright and look great but nowhere near OEM quality in terms of lighting up the road. I might click some pics and send them via email.

    Anyways, I’m thinking of switching over to the OEM Xenons (not sure if I want phil/fly’s DRL led lights though; just want HID!!!) and I found what looks to be a good deal on brand new Euro ones (clear instead of amber right?). Now, I shared the links below, which seem to be all from the same seller start245 who appears legit. The seller lists them as EU with AFS: 8E0941029BP (L) and 8E09410030BP (R). Since my A4 originally had halogen, I will need the adapter harness, which you recommended Kufatec right?

    Anyways, these Euro Xenons will work with my American car right? The seller noted “Might require some modification for US models!”

    Since I believe you put the Euro ones on your former car, can you comment? Lastly, the H9 Morimoto HID kit (35w, 5500K) I have currently installed should be fine being moved to these Euro babies right?

    Btw, fog H9 Morimoto HID kit I had installed looks great though on the halogen fogs and I’m not blinding anyone! 🙂

  20. Sorry again but I never got an HID kit for my projectors. I guess this goes back to my question of whether I will need a new HID projector kit for the Bi-Xenons. Not sure if the H9 one that worked with the halogen and eagle eyes will work.

  21. Hi Mac,
    Those european OEM xenons should work, I don’t know why the seller says they won’t but I’m guessing its more of a liability thing…they work, and a large number of people are rocking those in the US (myself included). You can get them with or without the AFS, the AFS is the auto-leveling system and is kind of prone to breaking and costs about $100 extra, so I’d be tempted to say go for the non AFS version that is cheaper IMO. That auction also mentions the headlights lack the control unit for xenons (Ballasts) as well as the servo motor for LDR, so you’re still going to need to sink some money into them. You can’t reuse the H9 HID kit with these, they take D1S bulbs and specific ballasts that you’ll need to source. That cable should work and Tuning Fanatics shop is a legit seller, so you’re safe there.

    But I guess lastly I should say that if you never installed an HID kit into your projector headlights, then yeah that wouldn’t make much of a difference in light output and its totally understandable you’re disappointed. You might just want to pick up an HID kit for your current setup and see if you’re happy with the light output. I’ve heard a lot of people say they’re underwhelmed by the projectors you got, but since you already have them a $50 HID kit might make a big difference and convince you that you don’t need to drop ~1,000 on a new OEM setup (cost of the headlight housings, wiring adapter, plus new bulbs and ballasts).

  22. Hi Nick,

    Thanks for the quick response. Really appreciate it.

    Yeah, I agree these should work.

    The seller remarks note this:

    For vehicles with headlight levelling (automatic); Without control unit for Xenon; With servo motor for LDR; Might require some modification for US models!

    So, no AFS it looks like. However, it says “with” servo motor for LDR so I’m good there right?

    As for xenon (ballasts), where do I purchase the ballasts and servo motor for LDR needed? Sorry, I just want to make sure whatever ballast and servo motor I get are the right ones.

    I found the right bulbs on TFS though.

    Also, if I understand correctly, the D1s bulbs come with igniters attached right unlike D2s? So, no igniter is needed.

    I was thinking about getting an HID kit for the current projectors I have in the eagle eyes but I feel it wouldn’t make a significant difference in light output. They would just be brighter. The problem is the projector itself, which I suppose I could replace but honestly I feel like going OEM after trying these out for a month.

    So, I have a source for the headlight housings, wiring adapter and new bulbs. I guess the only issue is the ballasts and possibly servo motor needed. Actually, these ballasts in the link below would work right? I realize I’m going high-end with Morimoto but I don’t trust the cheap ebay HID kits on my Audi.

    My other option would to retrofit my OEM halogen housings (still have them ;p) right with new HID projectors, etc. right?

    I was looking at this kit but it’s pretty expensive.

    Anyways, if I get the Euro OEM headlight housings, Bi-Xenon Headlight Adapter Cable, D1s Morimoto bulbs and the Morimoto XB35 amp xenon ballasts I should be good?

    Euro Headlight Housings:

    Halogen to Bi-Xenon Adapter:



    I realize this endeavor is going to cost about 1K but I am investing in my car so I can enjoy her until she past 200K miles. At least another 5-6 years. Then, I might consider moving on to B10 or whatever Audi has at that point.

    Appreciate all the advice once again. 🙂

  23. Hey there – you are right, it says servo motor included, I misread that. All you need is bulbs, ballasts, and the wiring adapter. Those bulbs will work great. The Ballast I’m not sure about, if you wanted to go OEM it will mount to the underside of the housing really well. I’d be a little nervous using an aftermarket ballast with everything else OEM, just in case the amperage or anything is off and it harmed the wiring or threw an error. The ballast is actually the same that is used on a Chrysler 300, so you can buy from Chrysler a lot cheaper. Chrysler part # 5139061AA. ~$120 at

  24. HI there Nick,

    I’m about to fit retrofit the xenon headlights but I have one question, The xenon headlight can I use the manual levelling knob to adjust the xenon headlights or do I need to use VCDS or something to adjust and level them?

  25. There is a manual leveling knob on the xenons too, although you will probably need to use VCDS the first time to recalibrate them.

  26. Hi there,

    thanks for the speedy reply! I’m going to retrofit my xenon headlights tomorrow using the kufatek harness. How do i recalibrate them using vcds? Im guessing the manuel levelling knob should work on the xenon without having to do anything right?

  27. Correct, you can manually adjust without having to change anything in VCDS first. Step 3 in the post above has the instructions on what to do in vag-com once you’ve installed all of the parts 🙂

  28. Hi Nick!

    I have successfully retrofitted the xenon headlights, I have also changed on VCDS from halogen to xenon and everything works great. But I have one problem!!

    The height adjustment knob which is located next to headlight switch when i twist the knob the xenons don’t go up or down.

    Also VCDS won’t let me access xenon Range so how can i calibrate them?

  29. I have a friend that has a2007 A4 with the xenon lights with auto leveling bizenon light and he does not wan to buy those expensive lamps, he just wants ligths on the car, he order a set of halogens but the plug is diferente that what is the car, what can he do, he called Audi and they told him these are the part numbers he needs 8E0941029BD
    8E0941030BD, any suggestions will be appreciated

  30. I’ve never heard of anyone downgrading from xenon to halogen, that seems like a really expensive way to lose visibility at night. You need a wiring harness adapter, but I don’t think anyone makes one since it is a really unusual thing to do. It would be much cheaper for your friend to just buy new xenon bulbs than to try to retrofit the electrical system for halogen lights…

  31. Well we kind of knew that but if we buy the lights they don’t come with the lights but do u know if they come with the control to make the lights move and what do we need to buy for the demons, sorry for all this questions but we have no idea about this lights, thanks

  32. Hi Nick
    Love the blog! so much great help on here.

    I just found a pair for Xenons here i Norway where I love, but the Part numbers do not match the ones you wrote


    The AS is the part not matching, are these regular ones, or ones with curve lights? Bought them off a guy who claimes them to be spares for his DTM. they look un-used.

    Also, will the “” harness be enough, or do I need this kit as an example? if the lights have Curve-light, “”

    Sorry for lots of heavy questions, Would really appreciate if you took time to look this up

    Best regards

  33. The AS in the part number is actually just indicating it is a Euro housing. I can’t really tell if they are with or without AFS since the only description I can find of them are in German and I can’t read that. The link to the first (cheaper) wiring adapter from Kufatec should be fine if you just want basic capabilities, the latter version adds sensors for more advanced features but not necessary if you don’t care about that.

  34. Allright Nick. Thanks alot!
    Do you recommend some where to buy the Vag-Com? Not many coders in my Area of Norway, so might have to buy it to code the headlights myself.
    Best Regards, Mats

  35. I want to purchase the aftermarket projector kit on eBay but it is for an H9 bulb and my Audi is an H7. What hid kit do I purchase?

  36. Hi, was just wondering if anyone had a link on the adapter needed for the xenon headlights to work, as I was unable to find them on the link you had left Nick,

  37. Hi, thanks for the response, Was wondering if you would trust any adapters from an amazon/eBay site, as i am in Canada and would rather order off of one of those sites if you think they would be of the same quality,

  38. I have what is probably a dumb question but if the lights I’m looking at say “For vehicles with headlight levelling (automatic); Without control unit for Xenon; With servo motor for LDR”. Does that mean I will also need more parts than listed above or am I still good with everything covered? Thanks!

  39. This means that it doesn’t have ballasts included (control unit for Xenon), but has the automatic headlight leveling. You’ll need ballasts and bulbs, and it sounds like these are probably non-AFS, but it has the servo motor that auto-levels the headlights up/down just no left/right feature like AFS has.

  40. Hey there nick are you still here helping out with people and this new mod if you are i did everything you said d1s hid and ballast right i heard some people only youse the vagcom to make the high beams work but I tried driving one day but they turned off after 15 second and sometimes start flickering. The funny part is when the car is OFF and i switch the lights to turn on they stay on always !! Longer do you think its because I haven’t Vag-com it !?? I appreciate the answer !

  41. I would definitely start with vagcom updates – it sounds like an electrical issue where the car detects the bulb isn’t working, or not returning the expected signal/load, which could be because it’s expecting halogen electrical draw and instead getting HID electrical draw and then cutting off the circuit since something is wrong.

  42. Hey Nick,

    Thanks for the great post. I changed out my halogen lights to the Audi OEM AFS: 8E0941029BD (L) and 8E0941030BD (R) current ebay price $400 for the set, installed new bulbs and the Kufatec cable, set vagcom module 9 to xxx3x and the lights are amazing! Who wouldn’t love 4x more light?

    I have one problem and another question, first the problem, only my left drivers side light will adjust to the high-beams. The passenger side light stays on low-beam always. I double checked all connections and everything looks right. This passenger light came from an ebay vendor with 100% satisfaction and he said it should be perfect. Here was his response: “That certainly is peculiar I must say. I’m thinking it might be the flap that switches between hi and low beam or possibly the ballast.”— Thus I ordered a new ballast and will try that this weekend. Do you have any idea why this might have happened or an idea on how to fix this other then returning it and getting another one?

    Second question, as I mentioned I got the AFS version of these lights as the price was right but something tells me my car isn’t equipped to use this AFS feature with the simple two wire Kufatec cable. I see Kufatec offers a much more involved cable system for the AFS. I tried connecting to vagcom module 55 Headlight Range control to adjust the Xenon lights but it couldn’t find the module. Do you know this to be true or am I missing something?


  43. Hi Tim – that’s a great deal you got!

    No idea on the high vs low beams – IIRC it is the same bulb so in that case the seller’s theory sounds reasonable to me.

    For AFS – if it’s not throwing an error code, then it sounds like you’re probably okay. I think for non-AFS the adjustment is all done manually using the adjuster screws in the headlight housing, but I could be wrong here – been a while since I’ve done this…but AFS the bulbs dance left/right so there is more of a need to do an alignment, whereas non-AFS shouldn’t need as much adjustment once you got the height (up/down) right which I think is done via a flathead screwedriver.

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