Bi-Xenon headlamp query

[cobminor]

Hi,

I have had my xc90 for a few months and have just noticed a headlamp quirk. When I have the lights on main, or dip, and I switch to the other setting, the lights have increased brightness for a second or so before dimming back down to the level they were at before switching over. This happens when I go either way. Does anyone else notice this?, is it usual behaviour? Thanks.

[harveys]

Probably the ballast firing up the bulb again when it's ready hot ?.

[JADXC]

Hi,
iti is normal, all of the other cars i owned with Xenon lights did the same.

Turn on, increasing the light to max and then dimming back a bit.
Best regards.

[Clan]

Originally Posted by JADXC

Hi,
iti is normal, all of the other cars i owned with Xenon lights did the same.

Turn on, increasing the light to max and then dimming back a bit.
Best regards.

yes that is because they use several 1000 volts to fire up the lamp then after a second or two it reverts to 80 volts to keep it lit ..

[gmonag]

Sometimes, when the bulb is getting a bit old and tired it may not fire up the first time when switched on. That will produce the Bulb Failure message. Switching OFF and ON again will give it a second chance.
Also when switching ON, the bulb may flicker for a second or two as it settles down. This almost cause a collision for me in a supermarket car park. The daylight running lights (headlights) come on after engine start. I started, then set off out of my parking spot but the guy opposite interpreted the flickering as me flashing him out ahead of me and we almost met in the middle.

[cobminor]

Thanks for the help with this, I guess I can stop wondering about that one. I now not only know that it is normal, thanks JADXC, but why it happens, thanks Clan.