[TR] LEDs & Flasher

[Dave1massey at cs.com]

In a message dated 5/24/2010 6:55:55 PM Central Daylight Time, 
pj_thomas at comcast.net writes: 
> On 5/24/2010 3:15 PM, Foster, Stan (HP IT) wrote:
> >Bill, the Lucas design for the flasher relies on small elves that live in 
> a
> >metal container under the dash on a TR6. When you operate the flasher the
> >elves switch the circuit on and off. They feel the cold terribly however 
> and
> >rely on a heated bi-metalic strip in the box to keep warm and this heater 
> is
> >dependent on the wattage of the incandescent bulbs.
> >
> >If you switch to LED's the heater wont work, the elves will move 
> somewhere
> >warmer and the LED lamps will not flash. The solution is to use a modern
> >electronic flasher that could care less what the wattage is. The purists 
> don't
> >like them because the starting sequence is wrong (the elves start with 
> OFF)
> >and the cadence is wrong but I think most of us are happy if the flashers 
> just
> >flash.
> >
> >Stan
> >    
> All wrong.  If the you switch to LED's the elves will get confused, 
> panic and flash too fast.  They do the same thing when one of the turn 
> signals burns out.
> 
> Peter T.
> 


You're both wrong.  Everyone knows that any self-respecting elf wouldn't be 
caught dead in a metal can, even one as prestigious as a Lucas flasher can. 
 Those are trolls in those cans.  As everyone knows trolls are anti-social 
and prefer to hide out in secret places such as these.  What isn't as well 
known is that they are also luddites.  Once they learn you are using LED 
lights they will go on strike.

In actuality the classic flasher, typical of those used in our cars, used a 
series resistance and bimetal spring (as Joe alluded to previously) to open 
and close a set of contacts.  Since this heater is in series with the 
lights it is sensitive to the amount of current drawn by the lights.  It was 
designed to stop flashing if one bulb burns out providing the driver with an 
indication that something is wrong.  LED's will draw a lower current to the 
point that this feature will be invoked.  

The flashers that flash quickly when a bulb burns out is a more recent 
invention (circa late 90's) and therefore not "period" for our cars.

;-)

Dave