Chevy Alternator Wiring Diagram The H.A.M.B. . gahi's diagram is the correct way to wire a GM 10SI/12SI, and utilize all the benefits of that great design. The output and sensor wire (#2) should go to the main power distribution location, as shown, not to the battery. The #2 wire ensures the 14.4 or so output is fed to the entire system, eliminating any voltage drop. WHere do the 2 other wires from a Chevy 3 wire internaly . WHere do the 2 other wires from a Chevy 3 wire internaly regulated alternator go to ben know's the main one comes from the starter but where do the harnessed ones goto on a 77 Chevy 350?