I had the same problem when I bought my 2004. The inside door lock would not swivel back and forth, but the key worked perfectly and smothly from the outside. I watched the interal door lock move back and forth using it with a key, but i could not physically push it myself. I took the door apart, but nothing was broken, bent or out of whack. So, I went and bought this powdered graphite from Home Depot and puffed it all around the interior parts of the door. Within a few seconds the lock loosened up and I'm now able to lock & unlock from the inside. It might be a little stiff the first time I use it in the morning, but I put a little extra pressure on it with my thumb and it is definately like 90% better now.
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