OT: Electrical troubleshooting

[Jim Wright]

This is in regards to an '03 Kia Spectra, my son's car.  We've had an issue that has cropped up a few times lately, open the door, key in, dash lights on, headlights on, radio working, dome light ok.  Turn the key, thunk noise, all power dies.

Naturally I'm never around when this happens, by the time I can check the car, 5-10 minutes have passed, try to start the car, takes about 2-3 cranks then turns over.  Battery voltage reads 12.55, haven't been able to take a reading right as the issue occurs.

I'm suspecting the starter or related wiring, possible short killing all the power.  Tested ground to various points with my meter, no issues found, ground all around the engine bay seems good.

I've just downloaded the FSM and wiring charts, so far nothing in there covers what I'm observing  Any suggestions would be appreciated.