How I did it:
Google the partnumber. No results except for some parts database with no datasheets in it and a few ebay lisitings. Bummer, time to start hacking.
Since this LCD module is usually connected to a PC motherboard I am assuming the LCD drivers are present on the LCD module and not the standard(?) PC motherboard.
First probe around for Vcc and Gnd with power from an Arduino until something happens. I did that with no resistor attached, I should probably have added some kind of current limiting features to my setup.
First I used the ohmmeter to pin out some obvious ground planes to the ground pins, which turned out to be pin 2 and 4. Then poke around for Vcc using power from the Arduino.
Didn't take too long of probing around until symbols started flashing randomly on the screen, pin 14 for Vcc.
Then I loaded the blink sketch onto the Arduino and started probing around for the different symbols.
Thats pretty much it, making a notepad document for the pinout while probing around.
However there are a few details that I didn't work out yet:
1: pin 1 and 3
2: If I remove the ground from pin 13 backlight goes off and the mains powersymbol goes off, but the wierd part is the HDD symbol gets inverted.