Model A Ford Garage ~ Model A Electrical Wiring Diagram Click image to enlarge! Pictured above is the wiring diagram for the Model A as illustrated in Dykes Automobile and Gasoline Engine Encyclopedia Supplement, page 16. WIRING DIAGRAMS, Electrical system - Vintage Ford Forum Nice diagram of switch, but is the diagram showing the connection side of the switch or the side with the 9 bumps. I’m new the forum. My wiring is original but good.