Ford 8n tractor where does that starter button wire go?

On My 1951 Ford 8N, I have completely dissasembled, depainted, repainted and reinstalled everything. The problem is I can't remember where the wire from the starter button attaches. I thought it should attach to the starter solenoid but it doesn't work that way. This is a 6v positive ground system that has been coverted to 12v negative ground system. Where does that wire go?