What are some of the 2010 Ford Transit Connect door lock problems?

Depending on the issue You're getting, there are a few things that could go wrong with the 2010 Ford Transit Connect's door locking mechanism; most likely, You'll be seeing an electrical failure, either in one of the wires or in the door lock actuator. If You hear a buzzing noise while being unable to electrically lock or unlock the doors, then Your issue is most likely electronic and not mechanical. With that said, door locks are mechanical as well. It's possible that You have an issue with a mechanical component of the door lock, but this is much less likely. You'll need to remove the door panel in question, so that You can better diagnose specifically where Your issue originates.