Ford is not one to come up with too many ways to do something so I'd guess it is the same as a FSB. For older trucks the solinoid was on the inside of the fender. The arrangement there is Battery to one large post, starter to the other large post, and Key operated pick line to the small post, with any feeds to other circuits to the battery side. In newer ones, it is a relay with much smaller wire but basically the same, 12V to one main post, wire to solenoid on starter from other main post, and picked the same way as the other one was. the battery connection in this arrangement is to the solinoid mounted on the starter.
Put your truck information in your signature, it helps to get the right answer.
Good luck,

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