Hi @gtolun,
Welcome to the Dyson Community, and thanks for your question.
We’re always refining our technology, and sometimes changes are made based on testing or user feedback. In this case, we discovered that owners preferred to use the cleaner head with the illumination switched on all the time, so we removed the switch - it added complexity which wasn't needed.
Depending on exactly which machine you own and when you ordered it, you may see both versions of the illuminated cleaner head referred to in the User guide, or in imagery or video available online.
Hope this helps!