Question for Electronic pro...

Discussion in 'Electronics' started by Adam230K, Aug 18, 2008.

  1. Adam230K

    Adam230K Hardcore MB Enthusiast

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    Ok basically, since i got the xenons, i also got small blueish/whiteish lights (LED's) to go with them so they dont look all funny when i switch the xenons on. (yellow/xenon mix looked poo)

    But of course, the light on the dash to tell me i need a bulb replacement has come on, and i know this is because of the nature of the LED not requiring much current to run, thus the car things that they aren't there.

    My question is, is there electronical component that can be used in conjuction with the LED's to dissipate electricity (or use enough current) to make the car think there is a bulb there?

    And before anyone says anything about it being my xenons which are bringing up these dash lights... its not.
     
  2. whitenemesis

    whitenemesis MB Club Veteran

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    You need to wire a resistor in series with the LEDs.
     
  3. Dieselman

    Dieselman Banned

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    You mean in parallel.
    If it was in series it would reduce the current drawn by the LED but the bulb warning monitor needs to see leakage to Gnd. The ultra high resistance of the LED stops this so it appears as if a bulb is blown.

    A 5W bulb has 28.8 ohms of resistance. I'm not sure what the minimum resistance value the bulb failure moitor needs to see, but at 28.8 ohms it's going to get hot.
     
  4. whitenemesis

    whitenemesis MB Club Veteran

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    Thanks Dieselman, I always get those terms mixed! Luckily not in practise :)
     
  5. merc07

    merc07 Hardcore MB Enthusiast

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    Why not just get a pair of white 5w bulbs ? The ones that have the blue coating but are actually very white just like your xenons.
     
  6. Number_Cruncher

    Number_Cruncher Hardcore MB Enthusiast

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    >>it's going to get hot.

    a 12v 5w bulb would form the perfect resistor - if only there was a bulb holder with pre-formed connections and an enclosure in which to house it...
     
  7. davidjpowell

    davidjpowell Hardcore MB Enthusiast

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    Could make a useful engine bay light as well!

    David
     
  8. OP
    OP
    Adam230K

    Adam230K Hardcore MB Enthusiast

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    I boguth some of those "white" normal bulbs before think they were Phillips' ones, and i have to be honest they were almost identical to the bulbs i had on there before. So basically they're sh1t.
     
  9. Smatt

    Smatt Hardcore MB Enthusiast

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