As many others have reported the wire broke within a year of normal use (after professional installation). 

Customer service offered to send me a new mirror, which though seemingly helpful, was actually not because that would require an expensive install each time. No one seemed to acknowledge the horrible reviews this mirror is getting 

After talking to four different CS reps, one realized that for the TLC model, you can actually just get a replacement wire, which she sent me, without replacing the entire cabinet. It was simple enough (though a pain) for me to replace this wire myself, which I proceeded to reinforce heavily with electrical tape. 

The mirror itself is good, but this fatal flaw must be fixed, and support must be better. Kohler, get your ducks in a row with this!