LED taillight with an odd problem

[dannymax]

I bought this cheap little taillight off ebay and was pleasantly surprised at how it looks and works....originally buying it as just a plate light I now think it can function nicely as a brake/tail light also.

It seems to function as it should with the ignition on....taillight on brake/taillight on when either brake is used....but when the bike is started the brake comes on with the taillight even tho no brake is used. Pressing either brake has no effect, the light stays bright as if a brake was on.

Is this some kind of led backfeed or something? I don't have a problem disconnecting the brake lead and running it as just a taillight but if it can be made to function properly I'll do it.

http://www.ebay.com/itm/181318281258?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

I painted the metal inner fender corners after this pic was taken, they don't show at all now.

 

[VMAX1260]

check on the rear pedal where the rear brake switch there is a plastik nut whare the spring is. lighten the nut and you will be fine

 

[dannymax]

check on the rear pedal where the rear brake switch there is a plastik nut whare the spring is. lighten the nut and you will be fine

I checked that George....problem is everything works fine with the ignition switch turned on....it goes haywire after the bike is fired up.

 

[VMAX1260]

Can you dissable the front switch under the lever of the front brake to see if there is interference

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[dannymax]

Can you dissable the front switch under the lever of the front brake to see if there is interference

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I haven't gotten to that yet, thinking maybe it was a common problem with low end led lights. I will start it up and begin disconnecting switches and wires to see if it can be narrowed down. Thanks,

 

[VMAX1260]

Anything for u Danny ;-)

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[El Canadiense]

Disconnect the yellow wire (under the seat near the rear) to check to see if your power for the brake light is coming from somewhere else or just the brake system.

 

[Miles Long]

If your brake switches were working previous to installing this light, chances are there is nothing wrong with them now.
I had a somewhat similar problem when I was using LED tail/brake bulbs in my two taillight assemblies. The issue is the less resistance offered by the LED elements (like that problem with LED signals.) Turned out that this wasn't a problem at all-but an advantage. But that's another story.
Probably what is happening is that the increased brake circuit voltage of the running bike is enough to overcome the resistance offered by the tail light portion of the assembly, so that the brake light portion also is energized.
With the LED tail light in place, and the ignition ON, measure the voltage of the yellow(brake) wire, downstream of the switches. Betcha you will find juice!
I got nearly 6 volts.
This was caused by backfeed thru the LED tail lights, to the brake lights, because of less resistance.
Cheers!

 

[ninjaneer]

i'm with miles. try putting a resistor between the light lead and the bike lead. 10-ohm/20-W, maybe?

 

[Redbone]

Hmm, electrical noob here, are you saying that the power is flowing across the circuit board?

 

[dannymax]

I was wondering if it was something like that....there was a similar problem I had with a Lankee reflector to light conversion, he installed some little thing and it worked well afterward.

But, wouldn't you would know, I went out and ran the bike for about 1/2 hour (in the driveway of course) and it worked perfectly....shut the bike off and restarted a half dozen times and couldn't get it to screw up again. Both brake switches working as they should, back to taillight mode when released, seems good.

Not being one to trust my safety to a $15 light anyhow I ordered the Customs Dynamics light bars as planned but will keep an eye on this, if it repeats the problem I'll slap in a resistor....thanks for spec'n it out ninjaneer. :worthy:

 

[dannymax]

Hmm, electrical noob here, are you saying that the power is flowing across the circuit board?

I think that's what is BB....the led's don't use enough of the available voltage so it runs willy-nilly throughout the device being powered. I'm sure Miles & ninjaneer can explain it in more intelligent terminology. :biglaugh:

 

[DMAN999]

That running light is actually brighter than I thought it would be.
And those fender pieces look MUCH better now that you painted them black.

 

[dannymax]

That running light is actually brighter than I thought it would be.
And those fender pieces look MUCH better now that you painted them black.

Just what I thought Dennis, really not a bad little light for the money.

 

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The tundra must be defrosting up at BRC. I caught a glimpse of grass in the photo!

 

[Redbone]

The tundra must be defrosting up at BRC. I caught a glimpse of grass in the photo!

I noticed that too Mike! We still have 3' snowbanks and with 3 icebreakers opening up the big lake for shipping it means we'll be getting some lake effect snows before seasons end.:damn angry:

 

[dannymax]

The tundra must be defrosting up at BRC. I caught a glimpse of grass in the photo!

That's pieces of the Christmas tree Mike, I scattered them around for effect! :rofl_200:

 

[VMAX1260]

my tail light is a led light and works fine without resistors. the cables for low and high are two differend things. resisostors are not the problem. the resistors you install for instance to blinks are for not blinking too fast. take a multymeter and check the cable that you have the high rear light if 12v runs through it. if also lower current runs through it for example 9v then you must check your wirng. you should see current when you press the front or the rear brake

 

[dannymax]

my tail light is a led light and works fine without resistors. the cables for low and high are two differend things. resisostors are not the problem. the resistors you install for instance to blinks are for not blinking too fast. take a multymeter and check the cable that you have the high rear light if 12v runs through it. if also lower current runs through it for example 9v then you must check your wirng. you should see current when you press the front or the rear brake

Thanks George, I'll have to wait for it to screw up again tho, I guess, cause it's acting normally now. :confused2:

 

[Mr. Max]

I had exact same light (only with red lense) and it worked fine one summer. Now I'm going a bigger and better built led light, need a lot more modification to inner fender but I think it will look cool.. And this new light has a lot brighter license plate lights, four or five brightwhite leds.