Fahrenheit instead of Celsius for Audi A4 TDI 99

Hello,
'Then you spend some time looking for these stupid climate codes, and when you find them, you suddenly have a setting that isn't even described in them. So, I have a 1999 A4 Avant TDI (facelift, different climate control panel). Since I've been messing around with the hidden and so mysterious climate codes, the outside temperature and climate temperature display has suddenly switched to Fahrenheit.' I've already obtained the conversion tables – but it's quite tedious in the long run. Can I revert the displays back to Celsius?
Please help me.
Thank you!

[Translating...]

Versuchs doch mal mit:
Mit 'ECON' & 'AUTO' gleichzeitig läßt sich die Anzeige zwischen °C und °F umschalten
(Golf Climatronic )
Probieren natürlich auf eigenes Risiko, viel Erfolg