Lights problem

[ianmoran]

Sudden loss of headlight, speedo light, festoon and tail lights. Brake light still works, as does the horn. I thought it could be the ignition barrel was faulty, not responding to 2nd or 3rd turn. I've tried another one and the same problem persists.

Any ideas? If it was the light switch that was faulty, would the horn still work?

This is on a fairly standard S2 set up.

[Meds]

We need a bit more info on the system as the only S2 I can find with ignition is a TV with battery.
What type of stator? Is it AC or battery
Best guess at the moment is the fault is in the feed to the light circuit as the horn is working so you have power up to the head set and into the horn circuit
That would be the place to start looking and follow the wires from there- draw it out- check all,of the connections and if necessary bypass switches using shorting link to rule them out.
Another possibility is that a fault has occurred in the headset and blown the rear lamp making it look like you have lost all of the lighting circuit. check that the rear lamp is ok it might narrow the fault down a bit

[grandpa]

Hi,
As Meds states a bit more info 6 or 12v battery? etc.Do you have a multi meter
Have the bulbs blown ie are they blackened, check bulbs with meter or battery charger could point to over voltage from regulator which could blow bulbs but not horn also explains why brake light works.If you had an overvoltage it would only blow brake light if you were braking at the time of overvoltage.
Have you a good earth return ,use a piece of wire on side of say speedo light to earth (frame)
White wire from horn is earthed to complete the circuit when you press horn, its separate from light circuit
Grandpa

[GeorgeS]

Possibly a problem with the grey & purple wires coming off the foot brake switch? Worth a quick look underneath for breakages.

[Leotech]

This happened to me other day and it was the earth wire on the headlight bulb holder had come loose.

[ianmoran]

Thanks for the replies folks.

It's on an electronic ignition, A/C , bulbs haven't blown. All been ok for past 13 years.

Yes, I do have a multi meter.

[bookertmgs1]

Just fixed a similar problem - blew two sets of lights. Thought it was regulator.

Ended up being poor earth to headset. Wire in earth terminal had broken. was insulated terminal so I couldn't see it. Just touching when stopped but vibration when riding meant it lost contact and blew bulbs

Double check earths.