Black wire cut in 2004 lcd case? Where does this wire connect?

I opened a lot of Apple ibook g4 laptops.First one 2004 1.33 40gb hd.I checked and chimed and black screen.So I checked and the lcd screen had been disconnected.So easy connect and started osx.Was running fine,I put cases back together now automatically goes into sleep mode after loads osx and language installer comes up -sleep.Same again and again.The only different result is the ac in no batery,then sleeps -on -sleep -on , then screen light is dim????I opened lcd case to find 1 black wire is cut.Any one know where this black wire leads?I may have to just open another lcd just to find out.Any help would be of great help????