Engine fired up first time...but electrical help needed

Changed the solid state reg and checked the connections.

Thought I had the problem licked because the ammeter was showing only a slight charge......but the shunt wire does reduce the amount of measured current thru the ammeter so thats something?

Put a meter on the alt but its still pumping out 18 volts at idle.

Then something blew under the dash so we shut it down.

Going to check all grounds and under dash wiring tomorrow