Headlight query

Turned on the lights as usual this morning on my 2003 110 SW and side lights went on fine, but when I turned the headlights on everything went out. No sides, nothing. Did the relatively short journey using side lights only. I stopped to buy some fuses just in case and the problem persisted. Got back home, turned engine off and tried the lights again and hey presto all working fine. I suspect the switch but could it be anything else? I've had a sidelight issue recently where one of the bulbs kept blowing but that appears to be sorted now having cleaned everything up and replaced bulb holder etc.

Check your earths and the headlamp relay.

id suspect relay/earthing too, as L & R both sides and headlamps are independantly fused (or at least they are on a '96 )

Mine does the same occasionally, loose relay in my case

sounds like switch failure.

If you look at the metal contacts on the switch you will probably find the headlight contact has melted the plastic and began sinking into it.