I will go take a look at where I tapped mine. I used the dimmer line for the rest of the lights so when I dim the dash it dims the meter, and they are a good match. They use a 12 volt line and a variable 12 volt line. When voltage is missing on the variable line you get 12 volts for full light. When an amount is applied to the variable line, say 3 volts, you have a differnce of 9 volts to run the light with.
I will try and take some pics, hope I didnt confuse you more.