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I wanna figure out a starter, with integrated solenoid next
Actually all starter motors have integrated solenoid
But not a Starter Relay
New starter motor will have two connections, larger post is for larger cable going directly to battery power, and a smaller "S" post, 12volts on this smaller post will activate starter motor(the relay part)
Once you have the new starter with built-in Relay installed you have two options, assumes you have larger starter motor cable hooked up to new starter:
Remove the old starter relay from fender and hook all the wires from it to a "power junction block", basically a post, google it.
So battery cable and starter motor cable are now on the same post with alternator cables.
Then extend the smaller "S" wire from the fender mounted Relay to the New starter motor Relay's "S" connection.
"S" wire is from the Key switch, it has 12volts when key is turned to START, it activates the Relay.
Second option is to leave old starter relay where it is.
Move start motor cable to the Battery cable post.
Extend "S" wire to new relays "S" post.
Some may say to run a wire from old relays motor post(now empty) to new Relay's "S" post, which will work, but you now have two relays that can fail, and you are still running a wire to new starter...................so just use the old relay as a "junction block" and extend the "S" wire.