rdenis is the guy who can probably best explain how these systems work. What I learned reading the thread between rdenis and lexus, was that these electronics are complicated and have interdependencies. From an electronics point of view, what I would suspect is the most likely cause is one of the locking motors pulling too much amperage and causing the fuse to blow. An internal problem with one of the control modules is also possible, but I would have thought it would be throwing error codes.

I would hope that water leakage was designed out! But it is possible one of Ford's watertight connectors isn't watertight.