Don't know where I got this info so use care but here it is: Ralph Vin 1606 Two terminal plug: Spade connectors work well on these. Pin 1. Connect the brown and yellow wire from the idiot light. Pin 2. Connect a short jumper to the Batt. (alternator output) terminal. Batt. (alternator output). Connect the three? big brown wires that were connected to the output terminal of the previous alternator. Four terminal plug: This is the newer Delco alternator with internal regulator. It would probably be advisable to get a plug with pigtails and splice the wires. Terminal L: Connect the brown and yellow wire from the idiot light. Terminal S: Connect a short jumper to the Batt. (alternator output) terminal. Terminal F: Not used Terminal P: Not used Batt. (alternator output). Connect the three? big brown wires that were connected to the output terminal of the previous alternator.