LED Flasher Unit into Old Lucas 5FL Flasher Can

[svenedin]

I have fitted LED stop/tail lights. I then wanted to fit LED indicator bulbs but as most of you will know, an electronic flasher unit is needed to flash LED bulbs; an old thermal electromechanical flasher unit will not work.

I don't like modifications that change the appearance of the car and the LED flasher units are nasty looking plastic things that look totally different to the old aluminium can type. I believe there is a 3 pin aluminium can LED flasher unit available but only for negative earth. For us positive earthers there is no such thing. Of course LED indicator bulbs DO look a bit different in use (they are brighter) but there is nothing different to see at a car show.

I discovered that the top plate of the LED flasher unit is identical to the top plate of a Lucas SFB100. As I had a broken SFB100 I decided to swap the internals and it worked very well. I am told that this is called "restuffing" in the vintage electronics world. Taking modern internals and putting them into old cans. It is used for capacitors when the appearance of vintage equipment must not be changed.

Anyway, here's how I did it:

You will need an electronic LED flasher unit of the correct polarity for your car. These units must be earthed and have a fly lead for the earth.

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You will also need an aluminium can type flasher e.g Lucas SFB100

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Carefully lever round the edge of the LED flasher unit with a small screwdriver until the top plate pops out

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Then you then can withdraw the internals but note you will have to destroy the outer case to get the fly lead out with its connector still attached, No going back now......

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Now work around the top of the aluminium flasher can, release the top plate and remove the plate and internals

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[svenedin]

Ever wondered what the insides of a thermal flasher unit look like? Now you know.

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Now the LED internals are placed in the aluminium can but there's the earth lead. You could drill a little hole in the bottom of the can and feed the lead through there or do what I did and file a space in the top plate with a rat's tail file

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Now put the LED flasher stuff into the aluminium can and push the edges over with a small screwdriver so that it is secure.

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[svenedin]

Finally fit in the car and screw the earth connector down under a convenient screw.

You can now flash LED bulbs or any combination of LED and incandescent bulbs. Handy if a bulb blows and you only have an incandescent bulb to hand.

Note: if you have hazard lights this uses a dedicated flasher unit which must be LED compatible to flash LED bulbs.


Stephen

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[svenedin]

Just for completeness, if you have a hazard system that has a 2-pin Lucas thermal flasher unit 9FL, there is an identical format LED compatible flasher unit from Lucas WW10059E

https://www.feked.com/genuine-lucas-led ... UWrvZJTt2j

Since doing this, I have thought that a more elegant solution would be to rivet the earth fly lead to the inside of the can. Then the metal can being attached to the bulkhead becomes the earth and no fly lead visible. Soldering onto aluminium is difficult hence the idea to rivet instead. If done at the back of the can it would not be visible.

Stephen