B7 Audi A4/S4/RS4 Independent Fog Light Mod


Ever wanted to be able to turn your fog lights on independently of your headlights? After owning a B7 for over 6 years and getting countless questions about this, I’ve finally gotten around to doing this “5 minute” mod and it’s pretty slick, actually.


The modification is written up pretty well in the following link: Audizine DIY, so I’ll just expand upon some pointers and tips to make it easier, but essentially you just pop out the headlight switch and then use some copper wire to connect two of the prongs, then cover the old prong with electric tape. Lastly, update VAG-COM to rest of the world and you’re good to go!

Here is the rest of my pointers and notes:

  1. Firstly, some people have asked if this can be done with the VAG-COM only, i.e. no connecting of wires or messing with the headlight switch harness – the answer is a definite no, unless you have a very early (02-03?) B6 model, then it might be possible by just changing your VAG-COM to Canadian Settings. Anyone with a B7 will need to connect the prongs in the headlight switch, and most B6 owners will need to as well…
  2. While I still strongly recommend an authentic Ross-Tech VAG-COM cable and VCDS software, this can be done with a knock-off cable according to other commenters on Audizine. For specifics on how to program this via VAG-COM, check out this link where it says “Independent Fogs.” Your coding should be either 01011 for halogen headlights or 01021 for xenons with DRL.
  3. Wrapping the two prongs together is a little more difficult than you’d think, and whoever did the write-up has excellent craftmanship – mine is much uglier looking, but functional all the same. Use a flat head screwdriver to help guide and wrap the wire around the two prongs, as well as hold the electric tape in place.
  4. This mod will allow you to turn the fogs on when the headlight switch is in parking light mode by pulling the switch outward. Your Parking/City Lights will still be on, so it’s a good idea to put LEDs in there so it looks nicer as my DIY demonstrates.
  5. This mod is also compatible with my HID Fog DIY, so check that out, too…


All in all, it took me about 20 minutes, but mostly because I was taking my time. After testing it in my garage, it’s a nice mod and I like that I can choose when I want my fogs on or off, originally I thought this mod would turn the fogs on whenever the parking/city lights were on and that would be annoying. This is a great mod, and I’m not sure why Audi wouldn’t offer this from the factory – but thanks to PSYC0TIC ONE on Audizine for writing up a way to do this ourselves!

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. I have done this mod to my car and the only difference is that I can have the fog lights on with the running light. If I change to high beam, my fogs still shut off. I did not make any vag-com changes so I’m not sure if that’s why or not

  2. Hi Nick first this blog is awesome I have a question this mod can be done with out the vag-com software

  3. Not to my knowledge, Grover…but you can make it work with a cheapo $30 cable from eBay, if you’re trying to do this without spending a lot of money…

  4. I don’t know Grover, I have an authentic ROSS-Tech cable. I’m assuming any of the knock-offs on eBay are likely to work, but if you plan on keeping your car a long time I’d recommend getting an authentic cable for finding a friend or shop that has one that you can use.

  5. I’m new to the Audi world , always been a fan though , got the girl an 07 a4 and I’m learning along the way , I’m wanting to do the fog mod but what’s the vag-com deal ? What happens if I do the mod without it ?

  6. I’m not sure it will work without the coding, it basically changes the car to work as if it is in Europe where they have independent fogs rather than US where that isn’t an option. The Vag-Com cable is just an OBDII cable that lets you interface with the car’s software and reprogram things to unlock features/options in other countries or models.

  7. Where did you get the grille I’m just wondering if I can get one the same as that for my A4

  8. My car is just an a4 non s-line I wouldn’t mind a honey comb grille withe a carbon fibre filler plate but it’s just an idea. Also what front lip do you have would it work on the non s-line a4? I have been looking at the CUPRA r carbon fibre lip. Not sure if that’s what’s on this car or not 🙂

  9. Hey I really liked your blog! I do have a question tho! My right light seems to flicker and turn off more often. But I’ve noticed that it does it only while in motion. Then of course I turn off and off the switch and both my lights work but only for a short period of time. Sometimes I get lucky and they work the full time. For some strange reason when my left light flickers my dog lights do it as well

  10. Sounds like either a bulb or ballast is going bad, or you have a loose connection. Try switching the bulbs and seeing if the problem switches sides – if so, time to replace the bulbs.

  11. Just to clarify, when the my HID’s come on when set to auto, is there a way of also having the fogs come on as well? or does this mod only work with the city lights?

  12. Hey nick. Ever since I did the coding for this mod, my DRLs no longer turn on. I don’t have the led ones either, its the regular type of bulbs. I’ve tried all combination of light settings from inside the car but no matter the conditions they just stay off. Any help would be very appreciated. Thank you.

  13. Hi Mike – what is your exact coding in Central Electornics, and do you have xenons or halogens? The second to last digit controls the DRLs – it looks like the Audizine DIY says it should be either 01011 (Halogen) or 01031 (Xenon) but that would actually disable DRL for xenon – so I would do 01021 for xenons, because the second to last digit being a 2 is for Bi-Xenon Headlights WITH Daytime Running lights, whereas the 3 is for Bi-Xenons WITHOUT DRLs. Reference this picture specifically:

  14. Hey Nick, great site. I actually just ran into your site today. Need help… so I installed an LED set for the Fogs and my high beams didn’t work. I took the LED’s off to diagnose the problem and the High beams worked just fine.

    I also ran into this problem when I installed HID’s for the regular Low beams, I took those off and went back to stock and the High beams worked just fine.

    Please help… how can I keep my High Beams working?
    B6 A4 2004

  15. Hey Matthew – that is really weird. I haven’t done LEDs on this car but my guess is that something to do with the wattage or voltage being too different, so the system thinks there is an error and isn’t powering it. I’d maybe try doing an HID kit instead. Do you get a bulb out error on the dash?

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