here I go again

Couple interesting things here. Courtesy light exploded? Sounds like some sort of significant voltage event here. Maybe an overvoltage from the charging system? Are any other circuits or accessories in the car damaged? Alternators can put out lots of power under the right conditions and it could be possible to make wiring errors that could put over 100 volts to your car's electrical system. (Google "weldernator" to see how this works). Could be the same surge that blew out your courtesy light destroyed your ECU. I'd suggest disconnecting your alternator for initial start up, then troubleshoot the conversion.