Night LED on top of WXGA+ lcd is not coperating

[T400plus]

The small night usage "light" on top of the LCD is not lighting up. As of now i have given it back for
repairs. Any clue as to why it would have happened as i had not moved the T400 from its location for a
long time.It just stopped working a copule of days back when i needed it at night ...

[Harryc]

It's because you referred to it as a "night usage light" instead of it's proper name 'ThinkLight". It got insulted and decided it no longer had a reason to live .
I'd guess a loose connection or a bad LED.
http://www.thinkwiki.org/wiki/ThinkLight

[T400plus]

The engineers (thinkpad centre,mumbai) decided to replace the planar board. and now i am having a start up problem of xp.
I never remotely guessed that it was a motherboard problem as everthing else was working fine.
I will post more about the creatures unpredictable tantrums for other readers as I presume the piece I own is destined to be one of a kind in its family.
IT is a 2765T6U -9 cell , p8400 wxga+, 2GB ,ordinary LCD ...