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MG MGB GT V8 Factory Originals Technical - Flasher units

I'm fed up with replacing these cheap and nasty flasher units, so I now have an ancient, cylinderical, 3 terminal one off a Moggie 1000, which has been working perfectly. Recently I saw, on a French/Dutch BGT I was working on, an "electronic" unit, exactly the same size and shape as the moggie one, but in a translarent acrylic case. Does anyone know anything about them?............can't remember the name, sorry.
Allan

Indicator flasher units in modern cars have been 3-pin and electronic for years, people often use them to replace the standard 2-pin used in most MGBs in preference to fixing the bad connections that are usually the cause of non-flashing. They work on a different principle that isn't as sensitive to current and voltage, and whereas the original type slow down and stop as the current reduces (either from a blown bulb or bad conenctions) the electronic types speed up, flashing at double-speed when a bulb is blown.

Incidentally MGBs used 3-pin flashers in the early years, possibly the same type as the Moggie Minor, the 3rd pin in that case being used to flash the tell-tales, and I wasn't aware that they were any less susceptible to non-flashing when there are bad connections than the later 2-pin types.

Replacing a 2-pin with the same type may well start them flashing again, but then they 'burn in' to their normal operating characteristics and unless the original problems of bad connections have been removed they will stop flashing as well. If you use a modern flasher to avoid having to find the bad conenctions then you need to be aware that the bad conenctions will still be there and contributing to dim flashers.

When buying a non-standard type you need to be careful. There are after-market 'heavy duty' types which don't have the current and voltage sensitivity but they don't have the bulb failure indication either and so are a safety hazard. These are little more than hazard flashers, which are *designed* to flash at a relatively constant rate regardless of how many bulbs are left working or how long they are left flashing i.e. as a result of the car being abandoned after an accident or breakdown. If you replace it with a different type you need to disconnect one bulb and make sure you do get a change in flashing rate. They also differ from indicator flashers in how they operate: With indicators as soon as you operate the stalk the lights come on, then after a short pause they start flashing off-on-off-on. With hazards when you operate the switch there is a short pause, then they start flashing on-off-on-off. If you use the wrong type it introduces a delay in the lights warning other road users, which is another safety hazard (although so many drivers these days use the indicators as a 'magic wand' only operating it as they make the manouvere).
Paul Hunt

I pulled one of the cheap mand nasties to pieces. The heater strip was an incredibly flimsey strip of foil and was burnt out.
Allan

That is how they are all constructed i.e. that strip of foil glows red-hot and heats a bimetallic strip which opens the contact. With cheap and nasty you get what you pay for, which is why I almost aways buy from a recognised MG supplier. You can still get failures, but they should replace or refund. Lucas NOS (new old stock) is best if you can get it.
Paul Hunt

This thread was discussed between 20/07/2008 and 23/07/2008

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