Hi all, i see alot of people hooking a 12V supply to the 8 pin plug/ pigtail that comes off the speedometer of the 1990-1996 f150's to get them to power on to check the mileage. This is what i am trying to do. i don't want to put it in the truck to see the mileage, i cut off the pig tail from the junk yard so i have the plug just need to know which wires to use on the hot/neutral wires from my 12v supply (im assuming it's 12v?) Thanks!