This is a strange story. I jumped in my 2000 F-150 Ext Cab 2WD W/5.4 about ten minutes after parking it, turned the key and nothing happened. Okay. One of the guys I work with was there, so I grabbed my handy jumper cables (never before used to help my truck) and gave it a try. Nothing. Knowing just enough to be dangerous I took some screwdrivers, jumped the solenoid and it started. I drove to my office, parked it and went back to work. I had to stay for 24 hours, but fortunately I had my motorcycle there and when I got off I went home. That weekend I went to a Ford dealership and bought a new solenoid. I changed it. No difference. I screwed with it for about two hours and was completely stumped. Tried jumping it multiple times. I packed up my tools in the wife's car and was getting in the seat to leave and had an idea. I took the battery out (this shouldn't work, because the jumper cables didn't help). I took the battery out of the wifes car. Here is where I am stupid. Opposite terminals. When I hooked it up there were a few sparks. I got it apart REAL QUICK and twisted the battery in place until the cables went on. Truck started right up. Okay. Don't know how that happened, but replaced the battery. Everything works great, EXCEPT that when I take the key out of the ignition now, everything stays on for about seven seconds. The key in ignition dinger even continues to go off. When the truck is wet it works exactly as it did when I bought it with 16 miles on it. I tried swapping relays in the fuse blocks with others of the same part number thinking that if I can isolate it to one or two I can just replace them. No joy. I am not really worried about it, but does anyone have any idea what I can do to figure out what I cooked?