lawnflite 503,sit on mower, won't start?

have checked, battery and starter motor..both ok. checked fuse, all wiring and connectors, all safety features, seat sensor, brake sensor and blade safety. ignition looks ok, cleaned up all terminals. When sitting on, with blades up and foot brake applied, turn ignition key and don't even hear a click...could it be the ignition component?? any help much appriciated.