This wiring schematic shown here is the charging circuit diagram for the 1940-19489 Buick all models. The wiring schematic contains of some components like: solenoid and relay, 6 volt battery, ammeter, generator, and voltage regulator. Here we can also see the connection going to the ignition switch. Study this schematic to understand the charging system better to perform any wiring work. Click on image to view it larger in a new tab.