Rear Brake Light cannot get to work

[druist]

My MOT is this week. I have had a faulty rear brake light for some time. I know it isnt the bulb, as i have changed now to an led BMG or BGM LED panel. Earth is ok, both sets of lights work, front hydraulic i rigged up to the two brown cables in the headset and this is fine. Both RED cables in the rear brake sensor underneath foot brake are inserted fine.

I dont want to start changing sensor before I know nothing is wrong at the headset.

a) So it is either my sensor is broken?

b) A break in the cable (unlikely to me)?

c) A problem in the headset wiring?


It is a GP 150 (1979) but new ignition wiring and electronic ignition make for additional wiring.

I have looked at lots of wiring diagrams to figure this out. I am assuming it could be a black cable but why would a red cable change to a black or where would it? I take it the juncion box near my CDi is not related????

[Feeble]

Try disconnecting the cables from the brake light switch and connect their ends. If the brake light works now, the switch is faulty or suffers from bad connections.
One of them red cables ends in the junction box, check connection there, too.

[byron]

Try disconnecting the cables from the brake light switch and connect their ends. If the brake light works now, the switch is faulty or suffers from bad connections.

those switches do suffer, partly due to their location and sometimes because the pedal is resting on the switch, rather than the frame strut...
check that one of those wires has power going to it, and that the other one has continuity to the brake light LEDs

so does the front brake light work ?
what two brown wires did you connect it to ??

you only need one brake light for an mot, so if the front one works, just remove the rear switch, and tape up the wires.

[druist]

thanks guys, i have tried depressing switch by hand - no. Was going to try putting wires into another one when i get it thru post before removing.

I wired the hydraulic light wire onto the two browns next the the purple on the left side of headset as you are sitting on the scooter.

Another diagram indicates the blacks on the right side - 3 in a row (i think the bottom one is earth or at least doesnt do anything). At present i am cancelling out rear juncion box as a very good scooter company has just finished imola work and i noted they had neatened this up. If i pull the rubber cover off ..... probaly pull the red out anyway, but will go for this if other ideas fail.

If the wires are two reds - where do they change into whatever colour on the headset??? In most SIL diags (i think this may be nearer the DL design due to 78/79 being year of manuf. It had an old uk electronic ignition, no lugs on headset like the later ones. There is an indication of a cutoff battery tray but that may be just the frame design.

with Ignition changes, electronic ig, and addional wires have now left me clueless (Chris keep quiet pls ) about that is going where - little chance of following those two reds up, at least on my front yard anyway.

Gonna get a pic - or link of headset wiring as it is now. But i my money is on headset or brake sensor at the mo.

[Feeble]

If the two cables are single reds indeed and you got no red cable poking out of the wiring looms´ end in the headset, i would suppose that none of them reds runs into that direction because it´s a small and simple circuit from power supply (junction box or regulator) via stoplight switch to stoplight bulb.

[byron]

but does the front brake light work ?
if you wired it to two browns from the same connector block on the bulb holder, then it's not doing anything, other than connecting two wires that are already connected...
It needs power to one side [so maybe one of those browns], the other side should go to the brake light.... so either connected to the rear brake wire that then goes to the rear lamp, or directly to the rear lamp unit.

[druist]

but does the front brake light work ?
if you wired it to two browns from the same connector block on the bulb holder, then it's not doing anything, other than connecting two wires that are already connected...
It needs power to one side [so maybe one of those browns], the other side should go to the brake light.... so either connected to the rear brake wire that then goes to the rear lamp, or directly to the rear lamp unit.

Byron that makes sense, before i saw your email quoted i took pics and.....

Yes front brake is fine

[druist]

looking at that link is a little confusing. this one maybe better


http://picasaweb.google.co.uk/druist/Dr ... 2194135170

Will go out and get a multimeter as I have changed the sensor, one of the cables is fine, if i swap it around in the sensor the light dims. Dont know if that is relevant.
So now down to: Front brake light i wired to browns works

1. Headset wire?
2. A break somewhere in the red wire which goes to sensor then rear light. (i will get a multimeter to check this)
3. The junction box wire.

If anyone can see anything obvious in the headset pic- other than confusion. Wiring diags dont seem to apply or I am looking at the wrong one.

[dapper]

Don't mean to be nasty, but those terminations look s**te. I'd redo them all with VWP bullet connections and new shrouds, and I wouldn't recommend you ever do a Halogen lamp conversion on that headlight bulb holder, as that looks like the type that would melt in seconds. Sorry.

[druist]

dapper - I agree so no offence taken, you were just pointing out the truth. Could you recommend what sort of holder a halogen would require, also the correct size bullets. I noticed the ones i had in my kit didnt fit the sensor beneath the brake either. I have used the light for sometime and so far nothing has melted, that said it probably isnt earthed so good so its not giving out max power.

Any companies that stock decent bullet connectors instead of the cr*p on ebay would be welcomed. Is is 3mm for the headset ones and 5mm for the sensor? I am guessing here as i am miles away from scoot and micrometer, so not being lazy.

Any input would be welcome -