03 cts rain caused electrical shutdown
 

i was driving about 70 mph on an interstate. Rain storm occurred and shortly later my car starting going crazy, I got every single light on the dash then service electrical system then all gages froze where they were and then got service charging system then shortly later car stalled and battery was completely dead.

after towing to garage and hooking up to charger the next day car starts and gages work but display says low range on fuel system.
no loose connections found no obvious wires exposed or even any obvious wet area to explore.

Any ideas on where to look or how to prevent the repeat?