LCGB Forums

Ok, I purchased a atomic LED tail light a little while ago, as per Lambretta parts - it was hardly a straight fit anyway went to plumb it in to the scoot (SX150 6V Ducati DC electrics) using the ScootsRus website , tried the back brake off the battery- all good, tried the parking light off the switch- all good, however once the engine was running and I tried the lights, the front and rear worked ok but on trying the brake light, the headlight and speedo lights went off and no brake light, eh WTF? tried a few different combinations on the wiring which made the lights not work at all. Checked the earths etc, all seems fine, the bike was fitted with a new loom when I put her back on the road eight years ago, any ideas? Paul

did the back lights work before you put the led one on? it sounds to me that some were in the brake light curcit its earthing out so when you press the peddle it's working like the green wire and diverting all the power to earth

missing lynx wrote:did the back lights work before you put the led one on? it sounds to me that some were in the brake light curcit its earthing out so when you press the peddle it's working like the green wire and diverting all the power to earth

Yep, worked fine before, never had any issues, scootopia brake light switch fitted- all good

Are there three wires coming from the back of the Atomic one like the BGM type as the colours can be confusing have you used the correct earth from the unit ?

Toddy wrote:Are there three wires coming from the back of the Atomic one like the BGM type as the colours can be confusing have you used the correct earth from the unit ?

Yes it is confusing, I first tried what I thought would be the more obvious arrangement to the tail light (pink wire to the red wire, black to black, the other black to the earth) but that didn't work at all so I went to the ScootsRus website to see if there were any instructions on fitting and found they wire it with the pink going to the earth? very odd Paul

Is it this one?
http://scootrs.com/moreinfo.cfm?Product_ID=2554

In the tech notes it says the white is earth.
Try wiring it to a 12V battery to test it first.

just to confirm
Everything works, you hit the back brake no they all go off
What happenes when you take your foot off the brake, do the lights start to work again?
If so then there's a chance that when you hit the back brake it's back feeding the lighting circuits, so look for a short somewhere or there could be a wire crossed.
I would go back and use the original light unit to check that everything works ok, proving your scooter electrical circuits.
Then wire up the LED light unit one circuit at a time
Brake circuit first & prove everything works
Then wire up the back light circuit and see what happens.

Meds wrote:just to confirm
Everything works, you hit the back brake no they all go off
What happenes when you take your foot off the brake, do the lights start to work again?
If so then there's a chance that when you hit the back brake it's back feeding the lighting circuits, so look for a short somewhere or there could be a wire crossed.
I would go back and use the original light unit to check that everything works ok, proving your scooter electrical circuits.
Then wire up the LED light unit one circuit at a time
Brake circuit first & prove everything works
Then wire up the back light circuit and see what happens.

The original brake unit works fine, yes when you take your foot off the back brake the lights all work again, a shorting wire seems a likely cause, will investigate later, thanks for the help. Paul