No electrical power inside tracker

Hello, I was driving down the road at 55mph and my tracker just shut off and the engine quit. I was able to coast to the roadside and looked under the hood. I have good battery connections, the four main fuses next to the battery are all good. I metered them and they all are getting 12 volts and they have continuity. I pulled all fuses from fuse block under the dash and they are all good.

What power I do have is - Headlights, flashers, and horn.

I have no dashlights, radio, or ignition. When you turn on the key no door open alarm, no dash lights, no start, no radio. I have checked at the starter motor and I have 12 volts on the main wire. I have been looking around the web and some people are referring to "Main Fuse"

Does anyone have suggestions on how to proceed. How can I test the ignition switch? I have had no symptoms of a bad ignition switch, the Tracker has always run fine.

Thanks
1995 Geo tracker
5 speed
4 cylinder

pull all under hood fuses . look for rust or oxidation at the fuse connector plate. these things are notorious for corrostion down ther. good luck