Dunno what engine you’ve got….if Yamaha, the 10 pin harness supplies power/control from engine side harness to helm. Sounds like engine side is receiving power but no conduction to helm, so I’d unplug the helm side 10 pin harness from the ignition and test volts at the harness. If no volts, unplug engine side 10 pin and test volts. Just keep moving back till you find the volt drop.