I'm trying to button up my 500 project and I'm confused about the flasher. I upgraded to a 73 model sub harness to the regulator/rectifier panel to have the spade terminals instead of the bullets. Anyway, when I look online for a flasher unit they show to have two terminals. However, when I look at wiring diagrams they show three wires going to the flasher. I have three wires (gray, black, and green). Any idea what flasher I actually need? Is anyone aware of one that I can pick up at an auto parts store?