Problem with power door locks on 2004 Echo

[40_acres]

I can unlock the drivers door with the key, and click twice to unlock all the doors but can't lock the doors with the key anymore, I need to use the switch on the console. When I bought the car a few months ago the drivers lock worked fine, then recently started locking intermittently and finally just quit altogether. The passenger lock worked to unlock intermittently, now won't work at all anymore.

Any ideas what the problem is? Will the doors need to be taken apart to fix it? I hope other mechanics can work on this... I don't want to go to the local dealership because they are a bunch of crooks.