I have had the same problem for quite sometime. I have a 98 4 door Explorer and the front passenger door would not open when I got the vehicle. The outside inside handle did not seem to be connected to the rod and the outside handle did not work either. Today I finally took the time to try and fix it with a knowledgeable friend. My wife was tired of jumping across the drivers seat. Well it was a huge hassle. I was not able to get the door panel completely off, so we tried to locate the problem while one of us pulled the panel back. Nothing I did seemed to work. It seemed as if the locking mechanism was stuck. I finally found the problem. There is a rod that connects to the key mechanism that goes up/down when you turn the key. Somehow that particular rod was getting behind all the mechanical parts (sorry I don't know the correct terms, I'm no mechanic). So I had to reach my hand behind everything and pull on that rod. It was stuck behind something inside the door towards the rear. Well amazingly after over an hour of trying everything else when I pulled on that rod and got it unstuck from behind the other parts, I felt it release and the door opened using the outside handle. The rod had somehow fell out of the hole on the key locking mechanism and fell behind other parts. After getting the door to open I reconnected it and it immediately fell behind the other parts again and the door wouldn't open again. For the time being I cut it off and now the door works fine but it will not lock until I get new parts. The inside handle had a plastic part broken off also. It maybe worth a try to see if this is the same problem you have.
