I have used the diagnostics that allow you to move up and down each channel (typically 72 but some versions are less) and read the code. The decode of the numbers are shown on many VAG related forums but they don't seem to relate to my version of climatronic. As mentioned in another thread on here there is another way. Pressing the two extreme buttons before turning the key puts the unit into self diagnose mode (and it says it on the screen). The climatronic system seems to cycle all the flaps,