HELP!! I have a 90 chev pickup that the motor was stolen and when they took it they just chopped the wires off at the firewall. I need to wire the alternator. I know the lug on the back is battery voltage but can anyone tell me what the two wires in the plug do. Are they suppose to be live when the key is on, or is one alive and the other isn't. I can probably test the wires in the bundle if I know what to look for. thanx wnk