Not locking good

YOU may recall the problem I had a few months ago with the steering locking on my Ford Focus Zetec. Thanks to your help, Ford replaced the steering column, which they said was faulty. The bad news is it has happened again. The dealer couldn't locate the problem and told me they are not sure it's the same one, even though the steering wheel locked. They replaced the power steering fluid, saying that may have been the problem, but I'm not sure the problem has been fixed.