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LED upgrade for vintage filament bulbs

Discussion in 'Technical Q&A' started by John B, Aug 17, 2019.

  1. John B

    John B Formula 3

    May 27, 2003
    1,517
    NJ
    The brake, running and indicator lights on my '79 BB512 were pretty dim by modern standards. The other day I pulled up behind a pickup at a red light with my turn signal on and although I could clearly see the big amber turn indicator reflected in the trucks shiny tailgate I couldn't see that it was blinking. I thought the bulb must be out so I checked it when I got home. Nope, it worked, but in the daylight it was just hard to see that it was flashing in that huge boxer lens. I started thinking this could be a safety issue, plus it just looks lame. I've heard of people successfully converting vintage filament bulbs to LED on a variety of other cars so I figured I'd give it a go on my Boxer. Bottom line, with a little bit of research it was easy and I'm very pleased with the results so I'll share what I did. I got all the parts from Amazon for about $100 and they arrived the next day.

    Bulb types:
    Single Filament
    bulbs are for lights that just have one purpose, for example a reverse light, or the rear indicator lights on my Boxer. These have a single electrical post centered in the base and two locating lugs on the bottom that are symmetric. The bulb can be placed in the socket either of two ways and it won't matter as the post still makes contact properly. The LED replacements for these are type BAY15D.

    Double Filament bulbs are for lights that serve a dual purpose, i.e. tail light + brake light, front turn indicator + running light. These have two electrical posts on the base and two locating lugs that are asymmetric, one is higher up the side than the other. This is so that the bulb can only be installed one way as they are polarity sensitive so you don't mix the circuits up. The LED replacements for these are type BA15S.

    LED bulbs don't have filaments, but rather many small light emitting diodes along the sides and top of the bulb. These are made with the circuitry and proper bases to fulfill the respective roles of single and double filament bulbs.

    LED color. Since LED's are so much brighter, putting a white LED behind a red lens will actually make it look pink rather than red. Likewise, an amber lens will look pale (but bright). Fortunately, LED's are made that emit a variety of colors. In our case we need Amber, Red, and White.

    Resistance. Although LED's are brighter than incandescent bulbs they also use less power. Sweet deal, but this creates a problem as the flasher module is designed for the higher resistance of the old incandescent bulbs. The solution used to be to wire in a resistor into each individual line to the indicator bulbs. Fortunately, now there is a simpler solution. Just replace the flasher module with one designed to work with LED's

    Flasher Module. These are typically a rectangular black box that looks like a solenoid and is probably where the other solenoids are in your car. Flasher modules have three pins on them, a '+' and '-' opposite each other, with an 'L' 90 degrees opposed in between. The problem is modules are made in two different configurations. With the 'L' at the top, some have the '+' on the right, and some have the '+' on the left. You need to make sure the LED replacement module has the same configuration as the one you are replacing. My Boxer has the '+' on the right. The flasher module with the '+' on the right is type CF14 JL-02, "+" on the left is type CF13 EP34.

    The video below shows the "after" results. The pics show the types and quantities of bulbs I needed as well as the location of the flasher module on my BB512. This worked out so well and was so easy to do that I'm going to convert all my vintage cars. Incidentally, there are also small LED's to replace those little bulbs that barely illuminate your dash at night. That's probably my next project.

    After video:


    Running lights: LED's on the driver's side, incandescent on the passenger side.
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    What I used:
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  2. NeuroBeaker

    NeuroBeaker Moderator
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    Oct 1, 2008
    31,107
    Huntsville, AL., USA
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    Andrew
    Great post, John. :cool:

    All the best,
    Andrew.
     
  3. Ak Jim

    Ak Jim F1 Rookie
    Rossa Subscribed Owner

    Dec 23, 2007
    4,532
    North Pole AK
    Excellent job!
     
  4. Wade

    Wade Two Time F1 World Champ
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    Mar 31, 2006
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    East Central, FL
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    Wade O.
    Is there much heat/temperature difference between the filament bulbs and the LEDs?
     
  5. Jack-the-lad

    Jack-the-lad Three Time F1 World Champ
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    Jun 22, 2004
    35,972
    Isle of Luci
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    Jack
    Thanks, John.

    Please let us know when you do the instrument lights. I'm really interested in that.
     
  6. John B

    John B Formula 3

    May 27, 2003
    1,517
    NJ
    I believe LED's generate less heat.
     
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  7. f355spider

    f355spider F1 World Champ
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    May 29, 2001
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    Hugh G. Rection
    The old adage applies..."it depends". For an equal output, they are less...but many folks substitute very high output LEDs and they can generate considerably more heat than the stock bulbs. One needs to tread carefully into the unknowns...
     
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  8. Qavion

    Qavion F1 Rookie

    Feb 20, 2015
    2,637
    Sydney
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    Ian Riddell
    Note that 3 pin turn relays disappeared in the mid-90's. "Skud Ing Swiss" offer a somewhat expensive but comprehensive update package (with LED-compatible relays) for later model Euro cars with 7 pin hazard/turn modules. Not sure about USA/Canada/Japan cars. Their website mentions the risks of using cheap LED bulbs.

    With instrument lights, you have to worry about polarity, colour changes (affecting the character of the displays), dimmer compatability, etc
     
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  9. Mechanical Dad

    Mechanical Dad Formula Junior

    Aug 30, 2016
    371
    East Aurora NY
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    Josh
    Did an LED upgrade on my Mondial a few months ago and it was worth every cent.
     
  10. racerboy9

    racerboy9 Formula 3
    Silver Subscribed

    Nov 3, 2003
    1,846
    They do make LED filament style festoon bulbs. Put some in my Stratos dome light and it looks just the same but doesn't generate near the heat a normal bulb does. I am replacing all but the headlight bulbs with LED's mainly because the bulbs are much cooler.
     
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  11. Jack-the-lad

    Jack-the-lad Three Time F1 World Champ
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    Jun 22, 2004
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    Did you use LEDs for instruments, too?
     
  12. Mechanical Dad

    Mechanical Dad Formula Junior

    Aug 30, 2016
    371
    East Aurora NY
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    Josh
    Not yet. Just exterior as of now. Amazing the difference. Planning to finish swapping the bulbs this winter. Ran out of time to do them all. It was time to drive!
     
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  13. MerlinTech

    MerlinTech Formula Junior
    Sponsor

    Mar 5, 2010
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    Georgia
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    Wade Williams
    Be aware that the double filament bulbs with offset post have two configurations. One post is brighter than the other and they have offsets that can go two ways. I found that a car I was working on had one run light bright and the brake light dim, the other side was correct. After some checking I swapped the bulbs and found the offset post were different. The bulb had been replaced at some point, but was working incorrectly. Installed the correct bulb and restored proper function. Make sure that you match the offset that you need.
     
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