These LX470 have a piece of metal that fails in the ignition lock part of the switch itself.I have replaced three in the last 14 months. A bit of a bear to do your self at home, steering column has to be dropped down a bit, two security /tamper proof screws have to chiseled out of place and are awkward to remove in place. Common failure on this car.
Just to add a piece of information: after careful study, I was able to change this out without removing the column bolts. you will have to remove and loosen items to allow access to the back of the ignition casing. There you will find a small pivot hole that you will need a very thin item (I used a small watch repair screwdriver) to push a small retainer pin over. This will need to pushed to remove the broken piece and held while you install the new insert cam. I hope this helps save someone out there all the headache I was facing.