So I bought an 07 Rubicon and when I got it, the key wouldn't unlock the driver side door. I got a replacement lock cylinder and put it in today, what a pain in the ..... Anyway, after putting the new cylinder in, the door will unlock from the outside now, but it won't lock, you can hear something moving but not engaging fully, I can't tell what it is.

The other thing is that the latch in the door will occasionally hit the striker and not actuate. It's like trying to close a door with the deadbolt out, it just slams it back.

Any idea what I did wrong?

 

Figured this out. The arm on the end of the lock cylinder has a built in "dowel" and it wasn't properly aligned with the lock actuator. Therefore, it would push it to unlock it, but couldn't engage it to pull it back to lock it.