I have a XC90 and starting recently the air volume doesn’t work anymore. To be exact, you can feel very light air coming out of the vent even you turn the air volume to max. I went to a shop and was later told nothing wrong with the fan or the resistor. So they suspected it could be something wrong with the computers but since they normally work on American/Asian cars, they dont have the software for European cars to proceed further. On the way back home, I suddenly felt some steady air coming out, but it keeps at the same strength no matter how you play around with all those air volume buttons.
Any comments/suggestions? And how much this thing could cost me to fix?