Typical Alternator Wiring | It Still Runs Some modern alternators only have one wire as all the external functions are housed within the alternator and, as the alternator is fixed to the car engine, this completes the ground circuit. However, the majority of alternators have three or four terminals which wires connect to. Checking typical alternator wiring is a moderately easy task. how do i wire a GM 3 wire alternator | The H.A.M.B. how do i wire a GM 3 wire alternator. Discussion in 'The Hokey Ass Message Board' started by SpeedRacer2002, Sep 30, For the common garden variety Delco 3-wire in a typical non-pigtail hotrod application, Just that it seems like everyone seems to have a different suggestion for the proper wiring method on a 3-wire alternator. 64-72 charging system wire up using GM 3 wire internally Click to view on Bing13:2564-72 charging system wire up using GM 3 wire internally regulated just an idea on how to hook a GM 3 wire internally regulated alternator up Alternator DEMO Wiring, connection toAuthor: Chris CraftViews: 1 Wiring a Delco (GM) Alternator Wiring an alternator . This diagram shows how to wire a Delco (GM) internally regulated 3-wire alternator. This particular model (10SI, used in the 1970s and early 80s) is the one you'll find on the generation of GM cars most often used in demolition derbies.