Okay so this is another common issue people have been dealing with. It just so happens that the LCD backlight on a huge number of 3GS phones have gone dark and never come back. I happened to have the change to replace this on a customer's phone and it worked like gangbusters (like that word? haha). One thing I have to note though, this may not work for all instances since the backlight and the LCD of the phone is controlled by a number of things. However it is worth a shot! Pics of the surgery and stuff! I should have taken more pics, but I was too excited about the repair lol. Lame, I know.
New Coil In Package!
Busted Coil Removed!
New Coil In!
So before I get a million emails in regards to this repair, please know that this may or may not be a definite fix for you. I can do the repair for you, however you must understand that if it comes out to be something else other than the coil, it is out of my hands. I am continually learning about the inner workings of the Apple engineering so bear with me :)
I do not know if this applies to the 3G as well, but if you wanna be a guinea pig, email me, and if you're wondering about the "jumper" trick, I've tried it and it didn't seem to work, more then once by the way, solder points were PERFECT as well. So I don't know.
EDIT: This could also render the phone dead, as I had one that didn't respond well the the repair at all. Very weird, it was one of mine, but it is under warranty :)