Thread: Headlights gone haywire

I have a strange issue with the lighting system on a 89 110.

When headlights are activated only one side works which is currently the right.
When the high beam flash is activated. The left light works as high & low beam, and the right turns completely off.
When the high beam constant is activated. The left light works as high and low beam and the right low beam stays on (slightly dimmer), and high does not activate.

Dash lights have also gone dark.

All fuses are ok and lights work (as above) with all internal relays and jumper wires disconnected, so I do not believe there is a headlight relay

I mentioned it is currently the right, as after cycling the blackout switch all symptoms mentioned above, reversed (left to right). This was a one time only gig and cycling the switch again has not had any further effect.

Could it be the blackout switch, headlight switch, combination switch or something entirely different???
Is there a relay which controls the lights somewhere?
Where is the junction before the circuits separate into individual fuses?

If anyone could add some light to the problem I would be most grateful.

Thanks,
Gav.

As suggested, it could be a wiring issue - poor connections, typically, but not always, the earth connection.

But both the multifunction switch is likely to be the fault, and the main light switch could be too.

There is no headlight relay, and this can be an issue with reliability. The switches handle the current OK, provided that higher wattage headlight bulbs are not fitted (and have never been fitted). If expected to carry higher current, the contact area is insufficient, meaning that the contact gets hot in use. Since the contacts are mounted in thermoplastic material, this softens so the contacts move a bit out of position, reducing the contact pressure and hence reliability.