After replacing the screen, it appears that the backlight is failing?

MacBook Pro 15" Core 2 Duo Models A1226 and A1260 Troubleshooting

Hi,

Recently, an accident caused a huge crack on my MacBook Pro 15" A1260. I got the parts, and followed the instructions in the repair manual to replace the screen. However, once I finished the replacement, it appeared that the backlight is not working. I'm sure the LCD panel works, because if I look really closely at the screen, I can see my desktop/finder/icons, I can even see the change in brightness when I push the button. Before the replacement, everything but the screen worked fine.

Thanks