After upgrading from 3.4, you may find that the Climate view appears when it was not enabled before. This is due to a change in the way that 3.4 uses a particular AsBuilt.
If you wish to disable it entirely, please edit the following entry using Forscan and enter ‘00’:
7D0-04-01
xxxx-xx80-xxxx
This has been known to work on the mk3 Focus which doesnt have reliable climate controls in Sync.
excellent. might be worth adding it to the common issues 
Already in there!! 
Well ignore me then didn’t even check
Hi iv just installed the update to 3.4 and everything works perfectly apart from when I try to control my climate using my touch screen nothing works… Any suggestions on this I have already done a master reset with no changes.
please don’t ask the same thing in many different threads/topics
I updated SYNC 3.0 19205 to version 3.4 19200. Ford Focus MK3 (2013). Manual air conditioning. After the update, the climate and airflow stopped working. Anyone had such a thing?
As your vehicle did not come with sync 3 there is likely an incompatibility with your ac module, nothing I’ve heard of happening on any modern vehicle before
Is there any easy way to go back to SYNC 3.0?
No as per the documentation it is not possible, only 3.2 or 3.3