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Well I've wired my fog/DRL's so they come on when unlocking

Discussion in 'A4/A4 cabriolet/S4 forum(B6 chassis)' started by dpbayly, Dec 22, 2012.

  1. dpbayly

    dpbayly Member

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    Was board today finished all my christmas shopping so popped into work and set about wiring up my next mod, Ive done this mod to previous cars and always liked it so thought id treat the A4 to the same treatment.

    I originally wanted to tap into the power I needed to activate the circuit at source the ccm but after finding out its hidden in the foot well under the carpet and inside a water proof box I decided I would see about tapping in at the dome light and it was here i came up against my first problem due to it being a CAN BUS system it wasn't straight forward, i wanted to pick up the switched 12v power but the 12v power never actually turns fully off for some reason, when there's not 12v going up the wire there's 4.4v and this is enough power to mess things up wiring it through a relay as the relay dosen't shut off unless it goes lower than 4.4v, i then found that the earth is also switched so i ended up using this to activate a relay which then send a fused power source to my DRL circuit..... simple


    It all went fairly smoothly the only thing i cant get around is when unlocking the LED bulbs flash a split second before coming on i did try it using standard halogen bulbs and it didn't do it so im guessing its something to do with the way LED's work .

    Here's a quick vid of them working:

    Remote activation of my fogs rewired as LED DRL's - YouTube

    The way I've wired it up means i get no back feed issues when using the interior light of the drls independent of each other, they also switch on once you shut the car off and remove the key from the ignition and stay on till you exit and lock or till the interior light goes out
     
  2. stu_m

    stu_m Well-Known Member
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    Excellent looks like it works a treat

    So what parts do we need? Any chance you can do a quick guide?
     
  3. fallmonk

    fallmonk Turbo Sport

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    Very smart mate looks really smart am well impressed
     
  4. dpbayly

    dpbayly Member

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    Thanks guy's

    I'll do a how to with diagrams when i get a min, my install was a half done already because when i rewired my fogs to make them my DRL's I did it using a standard 5 pin relay instead of a 4 pin because i knew i would carry out this mod at some point and using a 5 pin makes it very easy keeping the normal DRL circuit and the auto turn on when unlocking circuit separate so there is no back feed issues at all while using the 1 relay.

    In the how to I'll write it up running the stock fogs running as fogs.
     
  5. dpbayly

    dpbayly Member

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    Here's a quick wiring diagram showing how to get your stock fogs coming on when unlocking:

    [​IMG]

    you need to wire it through 2 relays so that the circuit can be isolated when the ignition is switched on other wise if only the 4 pin relay is used you would have a problem that if the interior light is switched on while driving the fogs would come on too, so wire it as ive described.

    For the ignition switched power you can tap into the wire i used when doing my DRL conversion, This one as it becomes live when the ignition is switched on, grey and red wire multiplug is behind the n/s headlight

    [​IMG]

    You will need to fit diodes into the power wires to each fog to stop back feed issues and so it wont upset the bulb out warning system ( I've had to wire these up this way for a friend on his 3 series E46 for this reason it works a treat) i didn't have to use them on my install as i had rewired mine to run as DRL's so i didn't have this issue

    here's the diodes what i have from previous wire ups:

    [​IMG]

    I bought them from maplins there the 1N4001S

    www.maplin.co.uk/1a-silicon-rectifiers-46385

    By fitting these's they only allow power to travel in one direction down the wire thus curing back feed issues

    Think that's everything if ive missed something or somethings not clear let me know
     
  6. dpbayly

    dpbayly Member

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    for some reason i cant get the maplins link to work so you will need to cut and paste to check them out
     
  7. Inertiauk

    Inertiauk Member

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    So if you are sat in the car and manually switch on the internal lights, do your fogs come on with it?
     
    #7 Inertiauk, Dec 22, 2012
    Last edited: Dec 22, 2012
  8. dpbayly

    dpbayly Member

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    Not when the ignition is on and if you use the front map lights when ignition is off no the fogs wont come on.
     
  9. 666markyboy

    666markyboy Well-Known Member

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    I like this.... do you have a link for what you replaced your standard fog light bulbs for ??? and also what do you mean by the Dome light ??? is that the main interior light ?
     
  10. dpbayly

    dpbayly Member

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    Here's the bulbs i used:

    H11 XENON WHITE HIGH POWER 7.5W CANBUS LED CAR FOG LIGHT LED BULBS (pair) | eBay

    Even though they say there say there CANBUS you will still need a set of these to stop the warning coming up on the dash, dead simple to fit:

    UK STOCK 2x LED bulb TURN signal Light Load Resistor 50W 6OHM Fix Error Flash | eBay

    Yep the dome light im referring to is the main interior light, when you open up the light there's 4 bulbs 2 little 5w sidelight bulbs and 2 big 10w festoon bulbs and its 1 of these the big ones you need to come off the earth side of the bulb this can be found with a multimeter but mine was the rear (side of the bulb closer to the rear of the car) i came off.
     
  11. crazy88

    crazy88 Loving the anonymity

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    Which relays are you using? Do they have a diode between 86-85? I'd have thought pins 85 and 86 (of the 4-pin relay) should have been the other way around if there was a diode present inside the relay. I was just looking at the circuit and trying to figure out what happens and was a little confused.
     
  12. dpbayly

    dpbayly Member

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    No, it's just standard 12v 4 pin relay there's no built in diode so it makes no difference which way you wire those two terminals, you just need to fit 2 diode 1 in each wire between pin 87 and the fog lights.
     
  13. crazy88

    crazy88 Loving the anonymity

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    Ah, i see! Now it makes sense then, haha! I was looking at it from the perspective of having an inbuilt diode! :D Nice little post-christmas project me thinks. I'll get it working first, and then get some led fogs no doubt.

    Thanks for the guide though, i love it! The setup works perfect too, with how they copy the interior light etc for turning on/off, but still allow you to use it independently. Very clever dude!
     
  14. V6 Quatt

    V6 Quatt Well-Known Member

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    thithis posspossible with the headlights??
     
  15. dpbayly

    dpbayly Member

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    Yep you would just need to tap into the live side of any bulb you want it to activate.
     
  16. crazy88

    crazy88 Loving the anonymity

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    I'm confused again dude! :D

    Those diodes are spec'd to 1A average fwd rectified current, when the fogs are on will they not draw a lot more current then 1A?
     
  17. Point_Audi

    Point_Audi Vorsprung durch Technik
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  18. d21burggraf

    d21burggraf New Member

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    I am wanting to wire my aftermarket DRL headlights so that they come on with the ignition switch. Would I use the same diagram and wiring points that you listed or should I be using different ones? Thanks for the help!
     
  19. DEvz

    DEvz New Member

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    Hi, I'm looking to get my DRL to light up with my dome light so when i lock and unlock the car they come on and turn off, but i got them to come on with my sidelights. what relay would i use to do this and how would i wire this up?
    Hopefully you get back to me a.s.a.p so i can get it sorted :) Thanks
     
  20. BigCat

    BigCat Member

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    Nice job.....I don't think I have a canbus fitted...do all A4's B6 have it ????
     
  21. S4_dan

    S4_dan Fire up the Quattro!
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    Yes I think so, as you should have a 'bulb out' warning on the dash.
     
  22. ruffrida

    ruffrida Well-Known Member

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    Not quite true!!

    If you dont have full DIS then you dont have a bulb out warning light, i thought all Audi's had this, until i had my clocks upgraded in me 8L.

    if you have a warning light for your washer bottle, then your pretty much certain to have full DIS
     
    BigCat likes this.
  23. BigCat

    BigCat Member

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    Thanks. I dont have washer bottle warning or mpg readout on mine. Was not sure what DIS was, first Audi. Has anyone gone for the CREE kits with cooling fans from customled uk? Canbus cancellers built in.....
     
  24. ruffrida

    ruffrida Well-Known Member

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  25. BigCat

    BigCat Member

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    Thats them mate....bit pricey but 2 year warranty. Wonder if they cud be used for fog drl or would the fuzz just pull over forr having full fogs on. Is there a drl fogliight out there as a direct replacement?
     

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