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Tail lights in the boot cluster (hatch)

Discussion in 'A3/S3/Sportback (8P Chassis)' started by synthdood, Dec 28, 2007.

  1. synthdood
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    synthdood Member

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    On my sportback the inside part of the rear light cluster (the part in the hatch) is only used for fog lights and reverse lights. The other day I was behind a new sportback that also had the inside part lit with just the normal lights on (like on the A4). In my opinion this looks a lot better. I did some searching and found this: http://oooo-a3.blogspot.com/2005_11_01_archive.html Take a good look at the pictures in that article!

    It appears it is just a question of some VAG-COM coding to get the inside part of the cluster to also work as regular rear lights. The mentioned post deals with getting rear fog lights to work in the US and only mentions how all the bulbs in the rear cluster(s) operate but does not specify how to do the coding. I have VAG-COM, but I have no idea what setting I should be looking at. Has anybody ever done this? Or even better: Does anybody have this behaviour by default (I am guessing it may be set like this from the factory on the latest cars). I would love to know what your (long) codes in VAGCOM are. I think I should be looking at module 9 (centr. elect.)

    Edit: I may have found the correct settings.

    In VAG-COM Module 9:
    Byte 9: Brake Light left/right Rear as Parking Light (US Standard: 18%, EU standard 22%)
    Byte 10: Extra Function: Rear Fog Light left/right as Parking Light (US standard 12%, EU standard 0%)

    So it looks like in the EU the brake light is used at 22% and the fog light is not used at all while in the US both are used with the brake light at a slighty lower setting (presumably to keep things from becoming too bright). I'll try it out in the weekend.
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  2. benw123
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    benw123 Moderator

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    This is an interesting find! I've also seen the link before and wondered if it was as simple as putting in a double-filament bulb in place of the single filament, fog light bulb.

    Keep us posted - I don't have VAGCOM but there's so many changes around these days I might just have to get a cable.
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  3. synthdood
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    synthdood Member

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    Success!

    As soon as I got home last night I got out the laptop and VAG-COM cable and started experimenting. It works! My tail lights now look exactly the same as on the A4. I currently have the rear fogs set at 22% (same as the default for the brake lights) but I do think this makes the whole cluster a little bit too bright so I will try the US setting later today (fogs 12%, brakes 18%).

    While I'm in VAG COM there is another thing I will change and that is to have the the rear fogs on one side only instead of both sides. I don't understand that many cars are set up with dual rear fogs. It makes them look like brake lights and I find that dangerous!
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  4. Dandle
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    Dandle Member

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    I did this about 9 months ago to my sportback, not sure why they never sold them like this though. It took me a lot of searching on VW vortex to find out how to do it.
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  5. Dandle
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    You dont need to set both the inner lights to fog by the way there is coding for them to just be normal tail lights and one to still work as a fog light if switched on.

    To do that change Central Electronics, set Byte 10 to '18'. Then your fog light still acts as normal.
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  6. synthdood
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    synthdood Member

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    That is exactly what I am trying to accomplish. What coding did you use? Do you dim the fog/brake at 22% or at 18/12% ?

    Still need to experiment a bit further though. The rear fog coding is a bit akward and seems to be ambiguous. There are several bits in block 9 that deal with the same lights and i am unsure about the coding and some settings are probably mutually exclusive.

    for example:
    Byte3 bit1: Rear fog lights (0=2 rear fogs, 1=1 rear fog)
    Byte3 bit7: Rear lights(1=back light/brake light dimmed, 0=Back Light dimmed)
    Byte4 bit4: Activation of both rear fog lights
    Byte4 bit6: Rear fog lights deactivated

    - So if I want just one fog light do I activate byte4 bit4 or not?
    - What the hell do they mean with bit7?

    Also in VAG-COM, the Long coding utility and on openodb.org all descriptions talk about parking lights while in fact we are not always dealing with parking lights but with regular lights. Things didn't become clear to me until I looked at the German pages of openodb.org. There I noticed that they talk about Schlusslicht when they mean rear light and they talk about Standlicht when they mean Parking light. I am glad that I speak a bit of german :)
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  7. Dandle
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    Dandle Member

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    You can set the single fog light part up using the easy coding tick boxes. When you select long coding a long list of code comes up set the sidelights up by changing block 10s coding. You dont need to change any of the lights power outputs at all. Or change them back to what they were if you have changed them.

    Hope that helps.
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  8. Dandle
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    Dandle Member

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    I think your getting confused with the link you sent at the top. Thats just for activating the fog lights on american cars that dont have them. They do as standard though have the boot lid lights lit when the lights are on.

    Try this link http://forums.vwvortex.com/zerothread?id=2406766&page=1 it may explain better than I can. On what I think your trying to achieve.
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  9. N8
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    N8 Kowalski Details

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    Great post! Thanks, will my 08 A3 be okay? Or will I need to do this mod as well?
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  10. synthdood
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    synthdood Member

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    If your new A3 does not have this, the mod will be easy. You do need somebody with VAG-COM though.
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  11. synthdood
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    synthdood Member

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    Okay, I've done some fine tuning and I think I've got it nailed now. These are my settings for now:

    Control module 09:
    byte 4 bit 4 1 -> 0 (activation both rear fogs off)
    byte 9 22% -> 18% (rear breaklight as parking light)
    byte 10 0% -> 18% (rear foglight as parking light)
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  12. N8
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    N8 Kowalski Details

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    I will be investing in Vag-Com definitely!!!
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  13. Dandle
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    You dont need to change any of those settings. The parking light that you are changing is when the cars turned off and the indicator stalk is selected left or right it leaves a light on that side when you leave the car. Just change byte 10 to 18 and it will do what you want without mucking about with any other light settings. Assuming all you want is the boot lid lights to be lit when you have the cars lights on.
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  14. synthdood
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    synthdood Member

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    You are right about byte 10 but byte 9 definitely controls the brightness of the brake lights when the car lights are on and have nothing to do with the brightness of parking lights. I have tried it and I am sure about this. The English descriptions of Byte 9 on openob.org and in the Long Coding Helper is wrong where they talk about "parking lights". The German description on openodb.org is correct.

    The change in Byte 4 is to get the the fog only on one side when it is actually used as a fog light. In Byte 3 you can configure if you want one or both rear fog lights, but that setting is ignored if in Byte 4 the "Activation of both rear fog lights" is switched on. That is what I mean with ambiguous settings., two places to control the same thing.
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