LI 150 Special - Brake light OK but no running light - HELP

[harps2]

Hi

I am just finishing off a restoration of an LI 150 Special and just started her up yesterday and now need to sort out the lighting.

After a few loose connections and additional earth added I have got most of the lights working except for the Rear light - brake light works fine and if I swap wire still OK so bulb working fine but no matter what I do I cant manage to get the rear to light up - ANY SUGGESTION PLEASE??

PS its a 6V Non Battery with Ignition switch (not cut-out) - All front lights working - its just the rear that's NG


Thanks in advance for any assistance you can offer.

Alanb

[grandpa]

Hi Harp2
Is the speedo bulb working?.The rear lamp is powered by a black wire coming from the same connector as your speedo bulb.Check black wire at rear with meter.swop over the speedo and rear light connectors at the headset..Does black wire from headset to rear have continuity? Check that black wire from ignition switch is plugged in.You will probably find you have a bad connection where black wires are plugged into headset junction.
Good luck
Grandpa

[harps2]

Hi Harp2
Is the speedo bulb working?.The rear lamp is powered by a black wire coming from the same connector as your speedo bulb.Check black wire at rear with meter.swop over the speedo and rear light connectors at the headset..Does black wire from headset to rear have continuity? Check that black wire from ignition switch is plugged in.You will probably find you have a bad connection where black wires are plugged into headset junction.
Good luck
Grandpa

Hi Grandpa

Thanks for prompt response

Festoon bulb is working, headlight is working (H/L) - I can get speedo bulb to work but not using any of the 3 black connector positions - two other black wire (one from rear light one from ignition) but if i put wire from speedo into other spare socket it stays on in all positions of ignition key.
i tried running separate wire from tail light to headlamp connector - the only way I can get it to light up its to touch brown wire but then headlamp goes out? - confused yet as I am ???

[Wack]

With the ignition switch on the second click there should be power out on the yellow and black wires so unplug from the headlight connector block and test. You say the pilot is working so check the black has power. If not then the switch is faulty, but if it has power then check with a meter that you have continuity through the bullet terminals.For the front light to go out when you run a wire from the rear light may suggest a short in the rear bulb holder.

[harps2]

With the ignition switch on the second click there should be power out on the yellow and black wires so unplug from the headlight connector block and test. You say the pilot is working so check the black has power. If not then the switch is faulty, but if it has power then check with a meter that you have continuity through the bullet terminals.For the front light to go out when you run a wire from the rear light may suggest a short in the rear bulb holder.

Hi Wack
can you tell me how to test power out on black and yellow (I have basic tester) but not sure how to do - sorry, I think lack of power at black may be the problem as speedo light does not work off black postion in connector either - you say switch may be faulty - it is just H/L horn switch which is new or do you mean ignition sw faulty?

thanks for trying to help but I need ABC of how to test if you don't mind ha ha

[Wack]

Ignore the h/ bar switch as you have dip and high and presumably a horn so you need a tester ,either a meter set on ac volts or a test bulb to connect to the black and an earth. If the black gives out no power on the second and third positions of the ignition switch then it is at fault or it's black wire is damaged or loose on the connections.

[harps2]

Ignore the h/ bar switch as you have dip and high and presumably a horn so you need a tester ,either a meter set on ac volts or a test bulb to connect to the black and an earth. If the black gives out no power on the second and third positions of the ignition switch then it is at fault or it's black wire is damaged or loose on the connections.

OK I can test that tomorrow thanks - headlight switches on with ignition at 2nd/3rd so I guess ign switch is working but maybe not for black connections - will update tomorrow.

[EddieStone]

Sounds like you should check your earth - make sure the earth wire is properly connected to a point on the frame where the paint has been scratched off, and there is a decent connection to the light housing/light plate.

The brake light is working because it's earthing through your tail light.

I had a problem with my brake light that was cause by the filament of the bulb wasn't connected to the cap. When I tested it with a meter it was fine because I was connecting the leads to the end of the filament, but in the bulb holder it didn't work as it connects through the cap. That was a frustrating time, lol.

[harps2]

Ignore the h/ bar switch as you have dip and high and presumably a horn so you need a tester ,either a meter set on ac volts or a test bulb to connect to the black and an earth. If the black gives out no power on the second and third positions of the ignition switch then it is at fault or it's black wire is damaged or loose on the connections.

OK I can test that tomorrow thanks - headlight switches on with ignition at 2nd/3rd so I guess ign switch is working but maybe not for black connections - will update tomorrow.

Good news (sort of)
1 step forward - two back - found the problem (correction first problem) black wire from ignition sw had detached - no problem - resoldered and re-assemble - check for power at black terminals in headlight bulb holder - fine great assemble all headlamp etc and start scooter - STILL NO BACK LIGHT - also no festoon or speedo.

opened up headlamp and removed black wire from harness to back light - NOW all lights are working , festoon , headlights, speedo bulb H/L and horn all OK - STILL NO BACK LIGHT as expected - if I plug this wire in to black connection festoon and speedo go out and no back light.

tried new wire direct from rear light to headlamp bulb holder - same as above no festoon or speedo but headlight OK
MORE HELP REQUIRED PLEASE

[EddieStone]

I still think you should check the earths.

Having voltage at a bulb is all well and good, but it needs a proper earth or it will find a random way.

[harps2]

I still think you should check the earths.

Having voltage at a bulb is all well and good, but it needs a proper earth or it will find a random way.

Hi Eddiestone
for completeness, and as you suggest, I have removed all fittings from headlamp re-attached seperate earth to speedo, removed and refitted earth at rear light (mount to frame -good connection) - re-assembled and no difference..................

If I connect black wire from rear lamp to ANY OF THE 3 POSITIONS - speedo and festoon bulb go out but rear light stays off - if I leave it disconnected - all bulbs are lit in position 3 on ignition but no rear light of course - even if i run a seperate wire from rear lamp to one of 3 positions - same ----- festoon and speedo short and go out and no rear lamp???

2 days now and after finding the black wire off the ignition this morning there must be something else silly causing me the problem - just I cant see it ...................any more ideas will be fully appreciated

[Warkton Tornado No.1]

Reading this Post, it’s fair to say you are gaining knowledge & confidence, with the help of all the contributors.

If I were you, now, I would take a long piece of cable & connect in any old how a bulb (12v speedo bulb will do) with a flying lead that you can touch to earth.

I would then ‘prove’ that it works by connecting to the correct terminal (that works!) in your headset & earth wherever you feel like around the back light.

As you go through the procedure, try the rear bulb contacts (there should only be one earth) which should be the only one to allow the test bulb to light.

Now disconnect the headset end & touch your test (non earth) wire to rear light (non earth) terminals & if your test light works, you know you have a fault within the rear light itself.

I apologise in advance if this response in anyway seems patronising, but this method is a visual check rather than just using a meter, which is what most of us would do.

[harps2]

Reading this Post, it’s fair to say you are gaining knowledge & confidence, with the help of all the contributors.

If I were you, now, I would take a long piece of cable & connect in any old how a bulb (12v speedo bulb will do) with a flying lead that you can touch to earth.

I would then ‘prove’ that it works by connecting to the correct terminal (that works!) in your headset & earth wherever you feel like around the back light.

As you go through the procedure, try the rear bulb contacts (there should only be one earth) which should be the only one to allow the test bulb to light.

Now disconnect the headset end & touch your test (non earth) wire to rear light (non earth) terminals & if your test light works, you know you have a fault within the rear light itself.

I apologise in advance if this response in anyway seems patronising, but this method is a visual check rather than just using a meter, which is what most of us would do.

Hi - yeah learning lots but struggling to understand your comments - sorry my fault not yours

so i connect one wire to speedo bulb (solder) ands this goes to live connection, then how do i connect earth wire to bulb? sorryf

[harps2]

Reading this Post, it’s fair to say you are gaining knowledge & confidence, with the help of all the contributors.

If I were you, now, I would take a long piece of cable & connect in any old how a bulb (12v speedo bulb will do) with a flying lead that you can touch to earth.

I would then ‘prove’ that it works by connecting to the correct terminal (that works!) in your headset & earth wherever you feel like around the back light.

As you go through the procedure, try the rear bulb contacts (there should only be one earth) which should be the only one to allow the test bulb to light.

Now disconnect the headset end & touch your test (non earth) wire to rear light (non earth) terminals & if your test light works, you know you have a fault within the rear light itself.

I apologise in advance if this response in anyway seems patronising, but this method is a visual check rather than just using a meter, which is what most of us would do.

Hi - yeah learning lots but struggling to understand your comments - sorry my fault not yours

LATEST

OK separate wire from headset with speedo bulb attached wrapped earth wire round bulb and touched to rear light earth - bingo it lights, will check next step tomorrow - if it works I need new rear light bulb holder? - thanks for help

[grandpa]

Hi Harps2
Almost fixed then.Some bulb holders have a round insulating disc with the two contacts that are spring loaded .With the bulb out press the contacts down with your finger and check with a meter the contacts are not shorting to earth.you may need some sleeving on the wires behind the disc.If you have the bulb holder type that has two visible fingers touching the bulb contacts then you can actually see the bulb contacts.
Sounds like you have a short on your bulb holder it may be the short only occurs when the contacts are pressed in by the bulb
Good luck
Grandpa

[dave81]

Hi harps2
Have been following your problem with the light. Grandpas last comment made me remember a problem I had with my rear light which may help. I could remove the bulb with the light on and when I put it back in the light didn't work. I found that the insulated disc in the bottom of the bulb holder was worn and turning when I put the bulb in so that the contacts were not lining up with the bulb contacts.

[harps2]

Hi harps2
Have been following your problem with the light. Grandpas last comment made me remember a problem I had with my rear light which may help. I could remove the bulb with the light on and when I put it back in the light didn't work. I found that the insulated disc in the bottom of the bulb holder was worn and turning when I put the bulb in so that the contacts were not lining up with the bulb contacts.

Good tip Dave - will check alignment

[harps2]

Well here's the latest and unfortunately not good.

I suspected the rear bulb holder so at much expense ordered a new one and fitted today - Still NO REAR LIGHT !

I have checked from the headlamp with a wire plugged into correct black wire point (12v speedo bulb attached) and using the earth point of the rear lamp - It lights up.
I have tested with a meter from black wire in headlamp to black wire at rear lamp - no problem continuity OK.
All earths are OK and checked
All other lamps are working, speedo, festoon , horn H/L etc etc

I am stuck !!!!!!!! - please help me out here, i'm nearly there and want to get MOT done this week- any suggestions??????????

[Phil D]

Hi
Have you tried your test bulb connected at the rear light end?

[Warkton Tornado No.1]

Well here's the latest and unfortunately not good.

I suspected the rear bulb holder so at much expense ordered a new one and fitted today - Still NO REAR LIGHT !

I have checked from the headlamp with a wire plugged into correct black wire point (12v speedo bulb attached) and using the earth point of the rear lamp - It lights up.
I have tested with a meter from black wire in headlamp to black wire at rear lamp - no problem continuity OK.
All earths are OK and checked
All other lamps are working, speedo, festoon , horn H/L etc etc

I am stuck !!!!!!!! - please help me out here, i'm nearly there and want to get MOT done this week- any suggestions??????????

If I understand correctly, you have followed the process of elimination in using a ‘test’ wire & now have to identify the actual issue which has to be within the area of the rear light.

All any of us on this Forum have done is to try & ‘walk’ you through the process, but you should be pleased with yourself that you have got this far, however frustrated you might feel

Perhaps having proved to yourself the virtue of a test live feed, you need to do a similar thing with your earth.

You know that you have good earths in the headset, so I would suggest you take a temporary earth lead from that to the area of the rear light to ‘prove ‘ the rear light has a bad earth as currently (excuse the pun...) connected.

Once you have achieved that, the problem will become crystal clear & you will be able to select a good, local earth (lamp &/or frame)/select a good lead or whatever is necessary.

Sorry, again, if I appear to be patronising in any way, but I assure you (& any reader) that I am not! Neither am I a technical author, so please bear that in mind....