Wet dog smell in 2010 VW Routan

After the heavy rains in the Northern Virginia area lately, my 2010 VW Routan has a wet sock smell coming in whenever I turn on the vents. It goes away when I turn on the AC but without the AC, the smell is disgusting. This kids don’t want to ride with me unless we have the AC blasting. Will this clear up once the weather dries up or do I need to take in to the shop? It is still under warranty. Also, what do I tell the shop so that they don’t laugh at me

First do you have a sun roof? If so the drain may well be plugged. You should be able to pour water into the drains on each side and see it appear under the car.

Next is the drain for the water the collects from the water entering the grill right in front of the windscreen. It may be blocked with leaves etc. After it is clean you can buy a can of lysol, turn the fan on high and spray away.

Note: string trimmer line is good for clearing blocked drains. 

Good Luck