Rear brake light will not work

[grant57]

Hi all

Carb bird 1996
My rear brake light has stopped working with front or rear brake switches(changed both of them!)
Fuse OK and cleaned with contact cleaner
Its a replacement LED type unit
PLugged the Honda OE one back in still does not work
Dismantled and cleaned with contact cleaner the blocks in the front fairing, they looked pretty good but tried anyway

Need a new MOT, so all ideas very gratefully received as how to solve it

Many thanks

Grant

 

[CBRDEAN0]

Hi all

Carb bird 1996
My rear brake light has stopped working with front or rear brake switches(changed both of them!)
Fuse OK and cleaned with contact cleaner
Its a replacement LED type unit
PLugged the Honda OE one back in still does not work
Dismantled and cleaned with contact cleaner the blocks in the front fairing, they looked pretty good but tried anyway

Need a new MOT, so all ideas very gratefully received as how to solve it

Many thanks

Grant

Just a suggestion cos i have done it previously - are you testing with the ignition ON ?

Have you measured voltage at the wires for the brake light ? - just in case both light units are faulty.

When did it last work ? - and what work have you done on the bike since ?

 

[grant57]

Yes ignition definitely on

Have replaced front and rear switches, contact cleaned block connectors and fuzebox, tried another rear light cluster

I guess its a broken wire, I am crap at this kind of fault finding!

But need an MOT soon, so If I cant fix it its the dealers

Always my very last resort!

Grant

 

[Boggymarsh]

Does the tail light itself work? The only thing that seems to me to be in common is the stop/tail light bulbs.

 

[Boggymarsh]

This may be of use...

 

[CBRDEAN0]

Looking at the wiring diagram there should be +12v at the GREEN/YELLOW wire in the tail light plug when you press the pedal or pull the lever.

If you have +12v there then the issue is an EARTH wire.

 

[Jaws]

About the only place that is common to both the front and rear brake light switch is a join in the loom.. It is a green wire with a white tracer you are looking for..
Mind you, given the grief it will take to find a break, As a start and just to check, get a bit of wire and connect one end to the +ve side of the battery and tother to each end of fuse number 3.. If it starts to work you know you have a problem actually at the fuse block ( though further thought.. does the headlight flasher work ? If it does then the fuse block is all good )

Next step
Same basic plan.. Connect a wire to the +ve side of the battery and this time tother end to the green/white wire on the rear brake light switch ( easiest access point I reckon )

As this is a tester use a thin bit so you can poke the bare end into the connector and replace it on the switch ;-0))

If they then work you know for sure the fault is in the loom
At this point you have choices

1) Strip away the loom until you find the problem
2) using a decent bit of wire ( the same size as all the others on the bike basically ) and connect one end to the green/white wire coming off the fuse block and tother end to that green/white wire on the rear brake light switch

That will bypass any and all breaks

 

[Jaws]

Looking at the wiring diagram there should be +12v at the GREEN/YELLOW wire in the tail light plug when you press the pedal or pull the lever.

If you have +12v there then the issue is an EARTH wire.

If that were the case Deano, the tail light would not work either ;-0))

 

[ianrobbo1]

Grant, we could always kidnap the ol git on Thursday, and force him "using alcohol" to sort it for you!! h1d1ng2




:-0)

 

[CBRDEAN0]

If that were the case Deano, the tail light would not work either ;-0))

Tail lights working has not yet been confirmed !!

 

[ianrobbo1]

Yes the tail lights do work, Just the brake lights that dont, he has un plugged the after markets and plugged the standards in, and the brake lights still didnt work but the running lights did!! :dunno:

Seen em myown self!! :dunno:

 

[CBRDEAN0]

Yes the tail lights do work, Just the brake lights that dont, he has un plugged the after markets and plugged the standards in, and the brake lights still didnt work but the running lights did!! :dunno:

Seen em myown self!! :dunno:

Good - so it's NOT an EARTH fault.

I would be having a look around the area of the newly installed shock !! - trapped/cut wires etc

 

[Centaur]

The first post says IMHO that it is the rear brake affected. Is this correct or are both front and rear not working? :dunno:

 

[CBRDEAN0]

The first post says IMHO that it is the rear brake affected. Is this correct or are both front and rear not working? :dunno:

Just re-read it myself -

My rear brake light has stopped working with front or rear brake switches(changed both of them!)

 

[ianrobbo1]

ignition on, back lights on, NO brake lights at all, front or foot brake applied, new light panel connected, exactly the same, :dunno:

 

[Me!]

Does a direct 12v to the brake light make it operate? Is the bulb double filament and has the filament blown. LEDs in their basic form only work one way round. I'm not familiar with the led set up but could it be that the filament has simply gone on a standard unit and the led is the wrong way round on the other unit

?

 

[grant57]

Thanks all

Its an LED unit and only connects one way
Tried connecting the old bulb unit, same fault unfortunately

horn and flasher on the same circuit work ok


grant

 

[CBRDEAN0]

Thanks all

Its an LED unit and only connects one way
Tried connecting the old bulb unit, same fault unfortunately

grant

When was it last known to work ?

 

[Centaur]

Disagreeing with a God.

If that were the case Deano, the tail light would not work either ;-0))

The green/yellow brings the 12v+FROM both switches to the brake light whilst the white/green takes the 12v+ TO both switches from the fuse. The green/yellow join is in the loom. Check there is 12v+ at the switches and if so check 12v+ is at the green/yellow wire at the bulb, as Deano says. If the 12v+ is at both switches but not at the rear then there is a wiring fault. A bypass is then necessary.

Try taking 12v+ direct from the battery with a temporary wire to the green/yellow at the rear and make sure the brake light comes on.

 

[Jaws]

Bill, sorry mate but I think we can presume the bulbs are ok as two separate light units have been tried.
Therefore the feed to the switches is what needs to be checked, but yes, you are right.. And a +ve feed should be put on the white with the green tracer...

I need stronger glasses !