I have two later model GM alternators for 2 different projects. Both have room for 4 connections but one only has 3 pins and apparently you only use 2 of them. Do you use 2 in the one that actually has 4 pins....or 3....or 4? On the one project the connector is pre-wired with 3 pins and goes to the alternator with 3 pins. The other alternator is going on a scratch built wiring (Painless wiring kit ) and the diagram is confusing me. I'm just in the planning stage and trying to see what else I need. Here are two diagrams from the Painless manual for the second vehicle. It's NOT a one wire alternator. It is an internal fan alternator. THE OTHER ALTERNATOR
https://www.hemmings.com/stories/ar...however,,and "L" or the "S" and "I" terminals. in part Depending on the system, you will only be using the "S" and "L" or the "S" and "I" terminals. "P" is the phase connection for externally powered accessories, such as a tachometer or hour meter, and can be used as an option. "L" is the alternator indicator lamp circuit and in some systems will be the ignition connection. "F" is an external field monitor connection. "S" is the main power distribution connector. The "I" connection (when present) is for ignition and connects to the ignition switch (keyed on/off switch).
The Jalopy Journal
