Same problem on driver side rear door / window
I have the same problem on the drivers side rear door on my 2006 liberty. The door latch will open the first stage latch, but will not unlatch the second and final stage of the latch. It is the same case whether I try to open from the inside or the outside, so it can't be the child lock. Both problems happened at the same time, so I thought they were related.
I was able to pull the inner panel off without opening the door, but found no obstruction with the latching mechanism, so I believe now that it is 2 separate unrelated issues.
Were you ever able to get your door to fully unlatch? If so, could you please let me know what the problem was and how you fixed it?