Laptop Screen is very dim, but visible

I am helping a friend fix his laptop that has a screen that is very dim but i can still see some images. The laptop model is a Dell Inspiron 6000.
The things that I have tried:
-Use another screen that works
-Use another inverter that work
There are two things that I feel may be wrong which is the cable that connects the motherboard to the screen or the LCD switch is stuck causing the screen to go very dim, but i wanted to check the switch before i replaced the cable and I was wondering if anyone knew where it was.
Also if anyone has any other advice besides the ones i did then feel free to suggest them