ACC vent selection

[JohnnyD]

My ACC will not let me select the vents I want, it is permanently on defog. Which is probably the best if it's going to get stuck. I've recalibrated the ACC and I get zero faults. I did a search and this seems to be a coomon problem especially for the 9-5, however I couldn't find a good write up to fix it. I swear I've seen a good write up for that before but I just can't find it.

Can anyone direct me to a good write up for this repair??