Okay, if you smell it when the engine is off but defrost on, it is possible it is mold/mildew growing in the HVAC unit. Somewhat a common issue with modern vehicles. First thing to check would be the cabin air filter. It is in the dash, hiding behind the lower glove box. To get to it you flip up the upper door, then flip the lower one down, remove the 4 screws that hold it in place and gently pull it out, there are two clips at each side so it may come out a bit hard. Behind it will be a door that folds down and inside that is the filter. It is an ACDelco CF188, Hastings AFC1626, Wix WP10129, NAPA FIL 230129, and a few others depending on where you look. I have seen them come out disgusting if people don't know they are there. While you are getting that pick up a can of vent deodorizer. The stuff I use is sold at the local dealer and is a spray foam, you basically shoot it into any opening for the heater you can find including the outside air inlet, it foams up and kills off anything living in the duct-work.
Images (Click to enlarge)
Wednesday, November 6th, 2019 AT 4:02 AM