I ma pretty sure the above lay out is correct, another way to check is if u have a after market radio with a adapter harness, or if u still have the plugs u cut off, u can look at them and the side opposite of the lil snap lock is positive, but like i said i am pretty sure those wire colors above are correct, oh and like tek said a volt meter will do nothing for u since A/C current constally change between the zero line