When I start to run the AC it smells really bad. It's really gross!!

What can can I do?

Thanks in advance!

 

Need filters changed and system cleaned out. Have system checked for clogged drain.

 

You'll need a complete system cleanup, including dryer/condenser where the mold is. Once that's done, to prevent in the future, as with my W204 and W212, always leave the HVAC in AUTO mode. Adjust temp to desired, let the system do the rest. Auto mode also lets the fan run after you shutoff the car to dry things out.