Problem with headlight (light control box)

[scootergrisen]

My headlight on my Kymco Super 8 dont work right.
Sometimes it work for some minuts and then it just turns off for no reason and sometime later it turns on again.
It acts like a loose connection but i dont think it is because i have checked all the connections many times now.

I found that the 7 amp fuse to the "light control box" has melted some of the plastic on the fusebox and the plastic was inbetween the fuse and the fuseholder but i have fixed that and it diddent help.

In this video i have connected the wires just like inside the scooter only the wire that im touching is not connected to the CDI box.
lyskontrolboks2.AVI
Just by touching the wire with my finger i can make the light turn on.
I use a T connection from a tv antenne thing because the surface on the little metal box is rough and i can make the light turned on better.

Here i connected a 12 volt low amp transformer instead of the battery and only 1 light bulb.
lyskontrolboks1.AVI
Look how the light come on in pulses and then turns off.
It diddent work with the transformer and both light bulbs... i things its because the transformer couldent give as much amps as the batteri can.

Now the thing i would like to know is what signal is the "light control box" supposed to get from the CDI box ?
I measured 1,6-2,2 volt on the wire to the CDI box when its in the scooter and the engine is running and the headlight works.

Its as if the wire needs a signal like the pickup (pulser coil) is generating for the lights to stay on... like a ON OFF ON OFF ON OFF... signal.

PS : the box in the video is a "light control box" and not a cdi box eventhough they look the same.
Have a look at : http://mentos.wep.dk/scooterhjemmeside/elektrisk.html#lys_kontrol_boks

Please give your comment and ideas 

[zombie]

The wire you are touching is the "trigger wire for an Electronic relay" (transistor) The light box has the same symptoms as a bad cdi. Some of them will go bad with a little running time, and some of them will just fail. I would just replace the module!

[Shaka]

Interesting!  Could it be that the lights run off of an AC system?  I have read that many scoots do.  Or that that "trigger" wire needs an AC input.

[scootergrisen]

The wire needs a signal like the picture at the bottom for the frontlight to be turned on all the time.

If a ON - OFF - ON - OFF - ON - OFF and so on signal.
The faster the engine runs the faster the signal is.

The signal is then used to have to frontlight on.
And when the engine RPM drops below a sertain level the frontlight will dim and only get 6 volt instead of the normal 12 volt.

Oh yeah and i fixed the problem by changing the CDI.
The CDI had some kind of problem not generation this signal all the time...
Some time i did and the frontlight worked.
But sometime the signal was not made and the frontlight would turn off.

Another person had the exact same problem... and also after about 2 years.

Heres the light control box disasembled :
http://localhost/scooterhjemmeside/rodekassen_lyskontrolboks.php

I also made this video before bying the new CDI:
cditest.AVI
First i works...
Then it dossent work...

[zombie]

Thank you for the cool info. Intermittent electrical problems are the worst to track down.

[scootergrisen]

Yeah its harder to track down a problem thats not there all the time.

I was about to buy a new light control box but the man in the shop sayd i could check the fuses so i did and that made me do some more tests and finaly i could mesaure that it was the cdi that was the problem.

There was also a problem at the fuse just like the man asked me to check.
The fuse has gotten so hot that the plastic around it had melted and gone inbetween the fuse and the metal clip holding the fuse.... i dont know why this happend and if it might has course the cdi to stop working corretly.

[zombie]

Many times as a component starts to fail the resistance increases. The increase shows up as heat. That is the principle behind the fuse. To heat up, and melt the filament. Many times the increase is not enough to melt the element, but rather the surrounding parts. A long winded way of saying I think the cdi caused the heat in the fuse, and not the other way around.

[scootergrisen]

I have pictures of the cdi and light control box electronic if anyone want to have a look :
http://scootergrisen.dk/scooterhjemmeside/rodekassen_cdi.php
http://scootergrisen.dk/scooterhjemmeside/rodekassen_lyskontrolboks.php

I diddent know they where SO complex.

[zombie]

You keep find the coolest sites/info.! There are much simpler triggers than these, but for the cost of a new one they are not all that bad. Utube has loads of homemade cdi's they are all quite large, but simple to build.

[aloy_g]

what we did was we bypassed the LCB so that the headlights would not dim even at idle speeds.

[wordslinger]

I have pictures of the cdi and light control box electronic if anyone want to have a look :
http://scootergrisen.dk/scooterhjemmeside/rodekassen_cdi.php
http://scootergrisen.dk/scooterhjemmeside/rodekassen_lyskontrolboks.php

I diddent know they where SO complex.

...grisen, you r th' bomb.....