HVAC fan controls don't work

[Bdc101]

After purchasing our new 2012 35d, we noticed the AC works great but on our second or third trip, we turned it on full blast to cool the car off on a hot day and found that the fan only blew very slowly even when it was turned up to high.



In the following week's we've found that the problem is intermittent. Sometimes the fan responds to the control in the dash, other times no matter what you do it stays at the same speed.



When it's not working, you can turn the fan speed up and down and the HVAC display shows correctly -- it responds to the button push. But the fan never changes speed. The only exception is you can turn the fan off entirely and turn it back on, but when it comes back on it is at the same speed as before. Turning the A/C off and on works correctly during this time, as does the temperature dials.



The rear HVAC suffers from the same intermittent problem. (Our car has 4-zone HVAC.)



I replaced the final stage unit with a new Valeo part today and no change.



I checked codes with my Foxwell the other day and didn't find any, however, at the time the fan was working. I'll check again tonight or tomorrow when it comes back from running errands.



What else might I look into after the FSU? All my searching results have turned up the FSU and nothing else. Thanks in advance.