Try opening up the chandelier and looking at its radius....if it's set really low, you won't get much or any light at all.
Try to crank it up some to see if that helps.
Its the default light, I didn't copy it from Summitmist just so you know. Even copying it from Summitmist it doesn't work.
Edit: I even went as far as copying the lighting from summitmist manor on the Cell Window (the Ambient,Fog, & Directional).
Edit: I have come to the conclusion that The light does not shine because this is an Interior that I retextured, Why this happens IDK, Doesn't in morrowind, so now the question is How do I fix it?