My 2001 A6 Avant had the 'flood' in the passenger footwells. The indicators then came on permanently. I pulled up the carpet to find the Comfort module sitting in some water. I pulled the module, drained it and cleaned up all the contacts. Now everything is working fine.

I need to know how to remove the pollen filter housing as I can see it is perished and there is a lot of crap around it (thus leaking into the heater). Plus if I squeeze the spongy seal it has water in. I have seen how many problems there have been with these cars using the search (its unbelievable and unacceptable), but I can't find how to remove the last nut at the back of the housing to remove it.

Any help would be great
Thanks
Will