intermittent dead electrical system - how to troubleshoot?
I drove my 2013 JK 2 door to the spray car wash today, turned it off, and then decided to reposition it. I got back into the Jeep and discovered that the electrical system was completely dead: no dash lights, no interior lights, and turning the ignition did nothing. Next I opened the hood, and nothing looked wrong, so I closed it and went back to try and start it again. Now the dash "door ajar" indicator was lit. The Jeep started right up (as usual). The radio had reset itself (lost all data), but otherwise everything worked, and continued to work, afterwards. I went through the set up stuff on the radio, and it too now works.
Yesterday morning, when I left my house to go wheeling, all of the NAV data in the radio had gone missing. I think this is related.
* The battery is plenty strong. No problems at all with the charging system.
* I checked the battery connections. They feel solid when I shake them, and there's no corrosion.
* The fuse box looks like ... a fuse box. Lots of colorful fuses, but no signs of wet or corrosion.
* The owners manual lists the fuse functions, but I didn't see a "main fuse" (or similar) on the list.
* Nothing around the battery or fuse box looks suspicious. Just dusty.
I am looking for suggestions on how to troubleshoot: where I can poke and possibly dig up clues.
Besides a battery disconnect, is there anything else that might cause the Jeep to temporarily go completely dead?