Horrible damp type smell when turn off cabin re-circ

[gbrall]

Recent hot weather have had the AC on and cabin re-circ. Now back to the normal scottish crap weather just put the demister on with external intake and there is a horrible dampy stale smell coming into the cabin, any advice how to sort, new cabin filter fitted and no change. Thanks.

 

[Bounder]

You can buy aircon cleaner, I think Wurth make it, it has a very long plastic tube that sprays disinfectant into the evap. unit and cleans it as it drips out the condensate tube.
I would start there.