E825 All Accessories work, No Power to Driveline

Hello. My name is Mark. New member. Me: above average DIY. GEM truck used lightly on ranch in California. I previously searched for solution prior to posting. 2001E825 owned 4 years. Batteries 6 months old. Delta Charger. Glass fuse good-tested continuity across ends. Small fuses good. Regularly used and charged. Parked in garage. Last night turned on ignition then white flash from right side of dash occurred. Now car has no power to driveline. When key is turned a click noise, like a relay sound is heard. No display on LCD. Green LED blinks as usual when connected to charging cable. Battery voltage 12.9. Lights and horn work. Parking brake switch appears good. At right side of dash components the original circuit board with two 10amp fuses was replaced by previous owner with some type of small box device that is connected to a large multi wire cable. To left of Delta charger is the OEM style controller (?) with 2006 installation date code.
No local service shops work on GEM car.
Any help very appreciated. Thank you.