I have a 1988 jx and yesterday while driving just went dead, I have no power to anything, horn , lights, radio, nothing! Battery is good, power to fuse block is good, all connections are solid as far as I can tell, WTH happened. Could this be ignition switch? I really hope this is a problem someone knows a solution for.

Think about it some more - do the horn & lights normally require the key?

Battery, battery connections or main fuse - one of the three - and don't just eyeball the block and shake the connections, they have been known to corrode & burn where you can't see it - disconnect the battery, unbolt the fuse block and remove it, check it with a meter if necessary.