The foot pedal part of the starter (that your foot touches, your "stomp starter") is just an offset lever to actuate the starter switch (that is physically located on the top of the starting motor, called "starter"). If you sat in the passenger seat, the starter would be in the vicinity of under your left foot.
The starter switch is connected to the battery- hopefully by a large cable; once it is depressed (by that foot action & extended lever), the starter switch contacts make an electrical connection causing the starter to come to life; the lever on the starter also makes a gear extend into the bell housing, engage the flywheel ring gear, & turn the engine.
Here's a
starter switch that goes on a foot-actuated starter. You can see the underside & the contacts I was trying to describe.
Adjectives made all this really confusing for me at first, so I hope this helps clarify some things. Remember, some things may also be in the truck that are not wired to function right now, or bypassed ; the push button "aftermarket starter switch" dangling from the dash could also be wired up to do any number of things- so I'd follow the wires to see where they went before I kept on switching it on/off.
Brad
