What fun...I removed my engine to fix some oil leaks and clean up some old grease and rat nest wiring. Weekend project ended up putting my truck out of commission for over a month. I busted the oil fitting connection on front cover and had to pull one off a rx-7 in junkyard. Anyhow, when I went to hook up the electrical I blew a fuse and lost power to my ignitors. Thanks to Jeff20B I was able to figure out what wire goes to the T connection on 1st gen RX-7 alternator. I weas wondering, what is the single blade connection in the back of the alternator which is closest to the swivel mount?
Alternators can be very generic. Stop by any alternator/battery shop and check their source book. I've seen "not used" in them before! It should say if it needs hooked up. It may be a detector wire for some other vehicle application. Some RV battery isolators offer a connection to the alternator for a feedback control of some kind. Could even be a connector for a radio noise condensor.
I don't think mine was hooked to anything either. Good luck!