Wiring up the GM 10SI Alternator - oldengine 10SI Alternator Wiring. The 10SI has three terminals (including those with a 1 wire regulator). The large "BATT" terminal which gets connected to your battery positive. Videos of old gm alternator wiring Click to view on YouTube13:2564-72 charging system wire up using GM 3 wire internally regulated alternator1 viewsYouTube · 3 years agoClick to view on YouTube4:40How to hook new alternator on old car13K viewsYouTube · 5 years agoClick to view on YouTube16:36gm 3 wire internally regulated alternator hook up how to90K viewsYouTube · 3 years agoSee more videos of old gm alternator wiring Wiring a Delco (GM) Alternator - hartin 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.