Hit a problem yesterday I haven't seen yet. I drove about 35 miles, no issues whatsoever. After the car sat for about 5 hours, I hit the key, the glow plug light went out after about 5 seconds, hit the starter and EVERYTHING electrical went out. No headlights, dome light, radio, nothing worked. Lights out COMPLETELY. After about 5 minutes I heard a hum, and all the lights came on again. I went through the same start sequence again, and the same thing happened. This time, no hum. Everything is still dead. Couldn't do much troubleshooting at the time. Anyone have any ideas what's going on?