My 2006 F-150 has an intermittent charging system problem. On our road trip a couple of summers ago the alternator appeared to have gone out. We were able to get off the highway and to a near by auto parts store and I changed the alternator out. Later that week on the way home the same thing happened in the middle of the dessert. We finally got towed into a town in Arizona. The local Pep Boys. They determined that my brand new alternator was bad. They put in a new alternator but I kept the core. I took the core into the local parts store and had it tested. There is nothing wrong with it. Recently the "Pep Boys" alternator was going in and out. Sometimes everything was fine, sometimes there would be little or no indication on the Ammeter. Sometimes the battery light would come on, sometimes it wouldn't. Wiggling the wires on the "Pep Boys" alternator would sometimes correct the problem. I have inspected every inch of every wire. There is nothing wrong with them. I finally went back to the "Oklahoma" alternator. It has been working fine for a week. This morning the Ammeter dropped to nearly 0. No battery light. I shut off all electrical systems I could. The truck ran fine and I was able to make it to the house. After shutting down the truck I tried to restart. It was dead. I jumped it off and the alternator is charging just fine. What the hell could this gremlin be?