That is the G5 17" A1058 Inverter pinout with 6 pins. I took it down myself from the board with a multimeter and the ICs Datasheets.

12v is the main soruse

GND is ground

5V supplyes Op amp on the sheme that gives the niveau of backlight, It cant be lower than 5v so actualy it dosn't regulate the dimm of the light.

5v The second line Gives the Enable signal ot the inverter

Dont connect. It goes to a gate of two mos transistors k72 SMD and is protected trought a diod directly after the pin. It should turn on these Transistors but when I give it supply, the backlight goes off and doesn't turn on back again when i remove the supply (I tried 5v) Fixed it with reset of the PSU.

3.3 v. Again goes on set of MOS transistors. Their gates should be capable of taking up to 5-10 volts. But I decided to play it safe. It makes the backlight brighter( that is the light dimmer). Whitout it the backlight works but isnt brighter as it should.