I have a question, I am setting up dual batteries in my 1985 fj60 with a externally regulated alternator and I have the surepower 4 post 95amp isolator along with all the wires run, except the excitation wire. When I fire the vehicle up with this setup the vehicle is cleary not charging. I do not have a voltmeter at the moment but going off the dash voltmeter its defianlty not charging. Does an fj60 need to use this fourth post and if so does which of the two wires on the back of the alternator does it tie into? Thanks I really appreciate any insight.