Changed my headlight bulb a couple of days ago due to failure....where's the problem I hear you say....today the LCD diagnostic is showing the same fault as when the bulb had blown when the bulb is fine and working..
Had a similar problem with my 05 12GS in the Spring. Bulb-knacked warning light was on at start-up and sure enough no light. Took the bulb out, looked OK so swapped bulbs over. Result working OK in other unit but still no dip light. Re-swapped bulbs, jiggled connectors, still no joy. 'Phoned local dealer (from whom I did not buy the bike and with whom I have a "tepid" relationship) who booked me in for a week later. Hhmmm. Anyhow, they told me at collection that the fault was in the connector and it was fixed. It didn't look to me as if anything had been replaced but the light worked so . Because they aint my mates I didn't feel able to query the repair details.
Bit of a pre-amble there - sorry - but it leads me to suggest you fiddle with the connector block and then try the battery re-boot idea. I did have a replacement rear light unit 2 days from the bike being new because the connector plastic body was split and thus allowing the terminals to move/break contact. Maybe they're all made of Phili-cheese!
