GP wiring issue

[garynonnah]

On my last leg of my resto......running 12v electro no battery.
All running good, but rear light not working , all other lights fine, incl brake.
Ive run out of ideas....any help would be appreciated.
tried two different bulbs...same result.

[Cgt75b]

Is the rear light housing earthed correctly earthed , make sure you have good contact with the frame. It could just be the bulb holder though. I have had the same issue recently and opted for a led one from Mb , five minutes to fit it and worked without issue.

Good luck with it.

[garynonnah]

cheers fella

[phil23fair]

Check you have got voltage on the bulb holder contact when your lights are switched on. I had a similar problem recently and it turned out to be the contact on the bulb itself. Instead of the usual crescent moon shaped bulb contacts, they were round. When the bulb was inserted in the holder the brake light was making contact but the rear light was missing the holder contact by about 2mm. Changed the bulb and it worked fine

[garynonnah]

STILL avin problem.....doin my head in...
Update fitted new led lens for rear light, changed front headlight holder,
but still no rear light

[rossclark]

Is the loom standard?

[Jono]

Hi mate
Sorry to hear of your problems.
Assume you have key ignition switch, does the speedo bulb in the head set light when the key is turned to the second position on my Indian GP's the same connector at the head light also feeds the rear light.
As the two are connected if speedo lights and the rear light does not work it must be either the black wire from the connector or in the rear light (earth/bulb or holder).
If the speedo light does not work either then it must be the feed from the switch. Ideally you need a multimeter if speedo light is ok to check continuity of the black wire to the rear light and to check bulb holder earth to the frame, although if brake light works would assume earth is ok.
Best of luck
Jono

[Tractorman]

If the brake light works the earthing will be good, as Jono says. You don't say if you have checked to see if you are getting power down to the light. If yes try connecting a battery to the light unit terminal and to earth and see if that works. If not you have a problem in the light unit or bulb. It makes life easier if you connect a battery up to the main feed wire to save you having to run the engine during fault finding.

[garynonnah]

UPDATE....problem sorted finally after my 4th LED rear light....
its seems when selecting high beam the current being drawn to rear light was
increasing, therefore blowing the resistors.....
thought about changing regulator, but was told by electrician that problem
can be solved by incorporating Zener Diode 12v 5w (two required) simply
soldered between earth and brake/light wire inputs.
This eliminates any power surge.....appy days.
cheers all.