Can't dip headlamps

[duncan]

Posting both here and NSXCB.

I run gas discharge xenon ignitors and bulbs on all four headlamps.

Went to use car last night, fully rotated lighting switch; L & R headlamp retractors up, hi[full] and lo[dip] beams on, blue hi beam warning light on.
Pulled turn signal/dimmer switch to go to lo[dip] beam only – nothing –all 4 bulbs still illuminated.

I’m aware that when the main lights are on, both the hi[full] and lo[dip] have a common feed, and that for the lo[dip] position the earth to the hi[full] beam is interrupted.

Today; pulled ‘dimmer’ relay; relay fully operative, [switching coil energized – main [earthing] circuit complete; no power to switching coil – main [earthing] circuit broken]

HOWEVER; with relay removed, [earth to hi[full] beam broken] the hi[full] beam remains on.

Jumping/un-jumping the ‘dimmer’ relay socket – no difference the hi[full] beam remains on.
Pull fuse 52, one side, both bulbs go out; pull fuse 49, the other side, both bulbs go out.
Remove main lighting relay – all 4 bulbs go out.

No pun, any bright ideas of where to go next.

Thanks,
Duncan

 

[duncan]

Kept lo[dip] HIDs, but replaced hi[full] beam HID lamps with halogen H1 bulbs; all now OK, hi[full] and lo[dip] operate normally and as expected.
Removed lamps, wiring and ballast units and bench tested these, both work fine.
Confused but relieved, I've no idea what caused the problem, all sets were installed 4 years ago and worked OK until earlier this week, any ideas?
Thanks for looking.
Duncan

 

[d.n]

Is the hi-beam indicator on the dash is staying lit when you pull the stalk for hi/lo beam?