LED Rear light wiring help please

[Paul75]

I am testing out a new LED rear light but cannot get this to work. I don't run any lights except for this rear light/brake light. looking at the wiring diagram I can see that the tail light runs into the light checker, I have removed the light checker (no room for it) and after reading other posts related to this believe I may be able to jump blue/yellow to blue on the main harness to bypass the light checker and enjoy a fully working LED........am I on the right track? This is a '79 special with 7 wires into the light checker BTW.

Also, as I'm only running a rear light (nothing else) do I need to jump any wires on the harness side of the Reserve Lighting unit OR can I leave it off without jumping wires? I understand that when this is jumped it's done so with blue/yellow and blue/black.

Paul

 

[Paul75]

Guys if anyone could just confirm if these wires to be jumped are correct or not I'd be super grateful!!! Wanna get the soldering iron out after work!!!!

Cheers guys

 

[TwoManyXS1Bs]

... looking at the wiring diagram I can see that the tail light runs into the light checker, I have removed the light checker (no room for it) and after reading other posts related to this believe I may be able to jump blue/yellow to blue on the main harness to bypass the light checker and enjoy a fully working LED........am I on the right track?

No experience with your modern bike, but that sounds right to me...

 

[Paul75]

I'm going to have a good look at this later so will let you know how this works as it would be good for others too!

 

[fredintoon]

Hi Paul,
you say ". I don't run any lights except for this rear light/brake light."
No headlight? No signals? No gauge lights?
Looks to me like you've the option to "simplificate & add lightness" to your bike by removing a fistful of mystery modules and several yards of wire?

 

[Paul75]

Nope, no headlamp and no turn signals, this bike will have a daytime MOT only. Does have gauge lights though......

 

[fredintoon]

Nope, no headlamp and no turn signals, this bike will have a daytime MOT only. Does have gauge lights though......

Hi Paul,
Wot? No 'Eadlight? No Signals? In today's high density English traffic? Not a thing I'd dare to try.
I'd suppose the LED light's low current draw is confusing one of the bike's mystery modules.
Try bypassing the existing wiring.
Check which way round the LEDs are connected. I read that they don't work if they are powered backwards.
And you did check the LED light was properly grounded?

 

[Paul75]

I'm taking the hardcore route with this build

 

[Paul75]

The above wiring worked......all good fellas!

 

[Paul75]

Guys this is odd. Gone back to mount the LED rear tail/brake light, the tail lights up but not the brake. The LED is not the issue. I cannot think of anything that's changed wiring wise in the last month. There must be something obvious that I'm missing GRRRR!

 

[Jim]

the LED rear tail/brake light, the tail lights up but not the brake.

You still have the "light checker" thingy hooked up?
Either that or it could be a polarity problem. LED's only take power from 1 direction...

 

[Paul75]

Hi Jim

Basically I removed the light checker and jumped the wires as above, this was a few weeks ago. I tested after this and the LED was working perfectly....I actually have 2 LED light units and both are the same.....

 

[Jim]

Did you try the front and rear brake switches?

 

[Paul75]

Yes Jim both front and rear switches......really, really odd and sure it must be something simple.....only thing I have touched (as fas as I can remember) was wiring up the horn switch.....

 

[Jim]

If it worked before, then it sounds like you somehow pulled a power or ground connector loose somewhere. You say the tail light works so that indicates a good ground at the bulb... start backtracking your power.
Sorry, that's all I got...

 

[Paul75]

Thanks Jim that's cool. Someone else may know, the horn, this is connected to the light checker and also the front and rear brake switches. Although I have not touced the horn, as I say I did wire up a horn switch using the pink wire. Could this be the issue somehow?

 

[Jim]

as I say I did wire up a horn switch using the pink wire. Could this be the issue somehow?

You could try disconnecting it and see if the brake light starts working.... again

 

[Paul75]

Will take a look...in between 'working' from home tomorrow...

 

[JRay77]

First I apologize. I haven't read all this thread. Those wiring diagrams give me a headache! I've had issues with the original wiring shorting out. The starters draw a lot of amps thru old wire with bare spots in the insulation. You can buy led turn signal relays. What Ive on my recent cafe build. I've found it easier just to strip all the old wiring harness out and start over. From the reg/rec to a new fuse box and there to whatever component.

 

[Paul75]

Thanks but all new wiring loom and I've installed new inline fuses......