What have you tried doing so far? Unplug and replug the cables first, however it sounds like the problem is half the backlight itself died, in which case you might need a new display.
From my understanding, this display uses fluorescent tube lighting which are integrated into the LCD. I investigated changing the tubes in my 2007 iMac years ago. For that model it was impossible to extract the tubes and replace them.
How do you know the cable is bad?
by Cameron
What have you tried doing so far? Unplug and replug the cables first, however it sounds like the problem is half the backlight itself died, in which case you might need a new display.
by da stumer
From my understanding, this display uses fluorescent tube lighting which are integrated into the LCD. I investigated changing the tubes in my 2007 iMac years ago. For that model it was impossible to extract the tubes and replace them.
by Simon Jones