If the starter is an exchange unit could be that the ground stud ( that I though was a bolt
) in the starter drive end frame ,went with the old starter in the core box.
This is a Denso starter , on my coach , I guess I should have asked if that was your brand first.
First Picture shows positive cable with red wrap, attached to the solenoid and the ground cable attached to the ground stud. I went under without my glasses so pictures are less than ideal.
Second picture is an end on shot of the solenoid cover and wiring , showing that my clean up after last years oil leak in incomplete.