My Honda 3013 rider has been a great machine for 12 years. While mowing it died just like you shut the switch off. My buddy trouble shot all the safety switches and found them fine. He said it was either the ignition switch or the module (epoxy sealed) behind the battery.
I located these parts on E-Bay and installed them. Still no go. Turn the switch and nothing,
Fully charged battery and clean terminals----any help appreciated. Howie

Have you checked the fuse? Check the groug wire opposite end from battery where connects to frame.