famous GCL electreical problems
I had all the symptoms you describe (blown 20A fuses, lights staying on, dead battery, engine cranks but it wont start, gauges going haywire, etc..etc..). I gave up attempting to repair it myself and finally took it to an electrical specialist who found the problem in the main wiring harness. He found two wires that have been rubbing against the chassis and have worn thru their insulation (thus why the problem was intermittent). He cut and replaced the worn out sections and then wrapped the wires for better insulation. It finally made sense when he explained that any momentery short affects the computer thus producing all kind of strange results. Good luck with yours and please let us know if this helped.