:welcome:
1) The SEAT SWITCH HAS NOTHING TO DO WITH EITHER CRANKING OR STARTING SO LEAVE IT ALONE
2) the cranking circuit goes from the battery to the ignition switch via a fuse ( check it ) then to the B terminal on the ignition switch, which bridges to the S terminal .
From there it goes through the PTO switch, then the brake switch and finally to the control terminal on the starter solenoid.
Get your test lamp out & follow it through.
Battery power for the starting circuit generally gets taken off from the hot terminal on the starter solenoid, to save wire.