To test pinouts I would recommend getting either a molex or sata to ac adapter such as this one:
Interestingly I was unable to get the inverter to light without a resistor between the green and the 5V line. I expected this with the purple, but not the green. Also note that I am pretty certain the native power supply to the purple is actually 3.3V. As it is simply an on/off I doubt the extra voltage will matter, but long term I can not say for sure. If you have an sata power source you should try to use the 3.3V line and if it works I'd probably lean towards using the correct voltage.
As you can see I left the dimmer floating, there are various ways of making a dimmer, but it is not necessary as the backlights appear plenty bright by using this method. Just as a reminder for those of you hooking up to a molex/sata power supply. YELLOW = 12V, RED = 5V, BLACK = GROUND, GREY = 3.3V (only on sata). There is also nothing wrong with using an atx power supply and its various voltages, I simply found this easier.
*NOTE: After hearing from a reader that the screen flickered with the Red line connected to 12V and stabilized when connected to 5V (and then confirmed by another reader) I decided to recheck it myself. And 5V is indeed the correct voltage. I then went and looked at my old notes which showed "Red - 5V". I made an error when originally making this chart. I apologize for any inconvenience and have updated the above chart.