I agree with Jedwards. These are pretty tough mechanisms. Can you unlock the door from outside? Check for binding in the rod where it goes through the rubbers on the door frame. It should be well lubricated there. There is a finger at the end of your lock that runs between two bars on your door mechanism. When you turn your key, the finger moves the mechanism inside your door one way or the other to lock and unlock. That finger is attached by one screw to the end of your barrel. If it has become loose, it is possible that it does not reach the bar anymore. Where is that broken spring you are mentioning? At the handle end or at the lock end? I had a broken spring that I was able to replace. Personally, I'd try to fix this before thinking of replacing the whole thing. It is not a complex system. But when you think about it, it's not such a bad thing. It prevents you from locking the door with your keys in the car. You can simply lock your door from inside before leaving the car. As long as you can unlock it from outside, of course!
