I went out a few days ago to open the passenger door of my F-150 with the original factory key fob and it unlocked the drivers door but not the passenger. A few minutes later I tried to unlock the doors again and this time neither door would unlock! I tried to manually unlock the drivers door with the key but the lock wouldn't turn so I used the keypad to unlock the door. I thought it was just a bad battery in the fob so I went home and changed the battery TWICE and the fob still wouldn't work. I cleaned the battery contacts and checked all three batteries and they all checked good! I finally went and found the second fob and tried it and it worked fine, then I tried the first fob again and now it works! I've been using it for several days since then and it's still working fine. It appears that the anti-theft computer in the truck locked up and that using the second fob somehow cleared it. Has anyone seen anything like this before? I was very surprised that even the key wouldn't work!