Any fuse, or fuse wire, would be between the battery and the ignition switch. The same " hot wire" would provide power to the dash ; or an ignition relay ; and the momentary power to the starter relay to crank the engine.
Have you checked the power wire to the ignition switch with a test light or voltmeter?
99DSDP 3884, Freightliner, XC, CAT 3126B, 300 HP /ALLISON 3060
2000 Caravan toad, Remco & Blue Ox.