cabin fan

Anyone know just how to get to the air intake inside of the cab? I have that fungal smell starting that I've read about. They make a spray that the deal puts in there. But, I would like to try to fix it myself. It's a 2000 328i 4dr. Thanks, dale.

My cabin fan suddenly stopped working and that has affected the AC as well. Dealer says it could be the final stage resistor and could cost $300 to replace ( parts& labor). Want to know if you have encountered this issue and is the resistor the most likely culprit? Also costs to replace...