05 F150 FX4. Maybe once a week when I start my truck, which starts up fine, all other 12volt power is absent. No radio, wipers, no power to the train horn compressor....nothing. Meanwhile the truck is running fine otherwise. Typically , in about a minute the radio display will light up, and I hear the compressor come on. Strangely , every time, the wipers lag behind every thing else . Eventually , to date, everything eventually powers up and I'm on my way. I know this is going to be one of those pain in the *** things that will be next to impossible trouble shoot. If anyone has any thoughts , they would be greatly appreciated.