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Modify the BMW Turn Signal Module to work with LEDs

Discussion in 'The Garage' started by Poolside, Apr 2, 2007.

  1. johnjen

    johnjen Now, even more NOW!…

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    A little uC interface? To make it all work together? :deal

    JJ
    #21
  2. Poolside

    Poolside Syndicated

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    <BR>
    Yes that's what I'm thinking. Prolly start a thread when we finish this turn signal controller mod.



    AND Speaking of finish, here's where we are so far . . .

    The 'fast flash' when the incandescent turn signal bulbs are removed and replaced with LEDs has been 'fixed'.

    At this time we're working out a way for the turn signal controller to operate in the the same way with LEDs.

    For example if an LED connection or circuit board fails, the other LED array and the turn indicator light on the instrument panel will 'flash faster' to let the rider know there is a problem with a turn signal.

    - Jim<BR><BR>
    #22
  3. R3B

    R3B Lazy Motorcyclist

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    I'm having the same problem with small aftermarket bulb lights, the left sometimes goes eratic both flasing like mad, would this fix fix that too, or will it flash real lethargic with a bulb signal ?
    #23
  4. autogiro

    autogiro Been here awhile

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    Man isn't that the truth!:lol3

    But the bike is probably version 1.1.1 itself.:D

    Auto
    #24
  5. Poolside

    Poolside Syndicated

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    <BR>Ok. After 150 or so messages, and most excellent lab work by JJ, the two modifications we came up with are a success :clap

    The modifications are harmless to the controller. And can be reversed. That is, if you cut either trace as shown below, it can be reconnected and the controller will again function as originally designed with 1156 incandescent bulbs.

    The lab tests and results that JJ conducted were so thorough that it enabled me to 'design' the modifications without going to the workbench. Capable technicians are a real pleasure a tell you what.

    The mods turned out to be much easier than we originally thought. No parts are added. The only modifications needed are to cut either one or two traces on the bottom side of the board. Pictures to follow.

    Important note . . . JJ is prepared to do this modification for latté money. He says he'll split it with me. Heh, we'll see :D I've already spent my projected profits on beer.

    - Jim



    - - - - -

    The bottom side of the turn signal controller

    [​IMG]



    The first modification is required:
    Cut the RED trace to eliminate the 'Fast Flash' when using low current LEDs.
    Cutting the trace forces the controller into the normal 'Slow Flash' mode.

    [​IMG]



    The second modification may or may not be needed:
    If you are using very low current LEDs in the array, the controller will flash only once, then stop.
    The threshold for 'low current' is between 250mA and 450mA per LED array or LED bulb.
    If the controller flashes the signals once, then stops, cut the RED trace as shown below.

    [​IMG]

    <BR><BR>
    #25
    jarik_bsu likes this.
  6. johnjen

    johnjen Now, even more NOW!…

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    By extra low current we're talking about under .5 amp. My test led arrays pull .26 amps each and most led arrays pull more than this, so the low current trace probably won't need to be cut.

    Also these pics show things in a magnified view. The board is just a little larger than 1-1/4 x 1-1/2" on a side. Its mighty tiny. :evil

    JJ
    #26
  7. Poolside

    Poolside Syndicated

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    <BR>
    I was thinking about doing a relative size shot. Here's a pretty good idea.

    [​IMG]


    [​IMG]
    <BR><BR>
    #27
  8. R3B

    R3B Lazy Motorcyclist

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    Great work, so simple and on an easy place, any slotfile will pull it of, maybe a bushnife will do, praise to you two :-)
    #28
  9. frankietheyankee

    frankietheyankee NJ Geezer

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    Oh man, we used to use that old "penny in the fuse" trick all the time! There are some inherent dangers though as I recall.
    #29
  10. jonasf

    jonasf Ich mag Sauerkraut

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    it works great:clap :clap :clap :clap :clap :clap :clap :clap :clap :clap thank you guye's
    wher should i sent the Latte-money?
    #30
  11. Poolside

    Poolside Syndicated

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    <BR>
    It was a fun project. We're glad you like it. You can buy a round later Jonas :D

    - Jim<BR><BR>
    #31
  12. gs'n

    gs'n odd knob

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    bump, thanks you folks for figuring this out!
    #32
  13. ElMartillo

    ElMartillo I See Faces...

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    Just a coupla questions:

    How does this mod effect operation with incandescent bulbs, if that's all there is available?

    Should this work with any LED replacement bulbs? I'm not making my own array, just replacing incandescents with LED equivalents.

    Thanks for the work in figuring this out, guys.
    #33
  14. Poolside

    Poolside Syndicated

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    <BR>As I recall, the modifications merely lowered the threshold current of the 'fast blink' mode in the turn signal controller. You know, 'fast blink' mode is when one incandescent bulb burns out, and the controller flashes the remaining turn signal bulb at a higher rate as a way to inform the rider that a turn signal bulb is burned out.

    Without that reduced threshold current modification to enable the use of LED turn signal bulbs, the turn signal controller always operates in 'fast blink' mode. This happens because LEDs use such little current that the turn signal controller always thinks that there's a burned out incandescent bulb.

    I don't recall there being any upper current threshold. So if you made the modification to run LED turn signals, incandescent bulbs would still work.

    There is one caveat however. Say you make the LED current threshold modification to the turn signal controller, and you switch back to incandescent bulbs. If one incandescent bulb burns out, the 'fast blink' routine will not work because the amount of current that one incandescent bulb uses will still be much higher than the LED threshold current of the modified turn signal controller. Other than that, the LED modified turn signal controller will work fine with incandescent bulbs.

    These comments are from memory. JJ might have something to add.

    <BR>
    #34
  15. eepeqez

    eepeqez Long timer

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    What's wrong with simply fitting a suitable resistor in series with the LED turn signal? Anyone capable of changing a turn signal lamp is capable of doing it and it's not like you fit LED turn signals to reduce electrical load; they're off the vast majority of the time.
    #35
  16. Poolside

    Poolside Syndicated

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    <BR>Nothing wrong with it. Though the mod is itself far easier than installing the resistors.

    And you have to get the resistors, and find a decent place to mount them. Those high watt resistors will not fit into the turn signal housing if you're using bayonet based LEDs for turn signal bulbs.

    Also, when using the large resistor, the 'fast blink' feature will not work with LED lights.

    And, the fellow that asked a couple of posts ago wanted to be able to use either bayonet based LEDs, or the original bayonet based incandescent bulbs. I do not know if the FET drivers in the turn signal controller can drive 2 incandescent loads along with the resistor load.

    The mod takes about 2 minutes. And is reversible if you like, or can be left as is. See post #25.

    <BR>
    #36
  17. xtzanos

    xtzanos Adventurer

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    Job done, excellent.
    Thanks a lot.

    Internet is a wonderful thing.
    #37
  18. def

    def Ginger th wonder dog

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    OK Jim and John, I'm about to do the mod to my turn sig relay to accommodate substituting LEDs at the 4 corners of my '01 GS but, I have a question; You are likely familiar with the strobe lights on LEO's cars...they flash in an uneven pattern...like flash-flash-flicker.

    On the GS, when the hazard flasher mode is selected from the LH triangle switch, is there a way to make the LEDs flash-flash-flicker (or something resembling that) using this relay and your collective genius?

    Finally, can you adopt the relay to perform Morse.....nah...never mind.
    #38
  19. eepeqez

    eepeqez Long timer

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    In Australia, and probably elsewhere, design rules (ADRs, FMVSS, CMVSS, etc) require hazard lights to flash together as a set and not to alternate.

    Apart from anything else, if they alternate, then it takes at least one or two complete cycles before someone seeing them can process what they are seeing (remember, it's an unfamiliar pattern) and figure out that it is in fact alternating, rather than changing from "just pulled over" to "about to pull out in front of me". When you're a hazard, you want to be recognised as a hazard immediately...
    #39
  20. def

    def Ginger th wonder dog

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    Here in the US, many folks drive down the road with their hazard flashers blinking away and as a result, hazard flashers tend to get ignored.
    #40