If you haven't tried it already, I would just take off the plastic cover on the inside of the tailgate and try to turn the key. You can look and see if something is stuck or binding with the cover off. Also it may be frozen up. A little bit of graphite powder might do the trick.
03' Freedom edition, 4.0, 5 speed, 4" zone lift, D30, Superior D35 with detroit locker, 4:56 gears, 33x12.5 bigfoot xt, 15x8 eagle alloys
God created all men equal, then a few of us became firefighters