Bad smells

I had this same problem in a '16 KW T680. Had the company mechanic look at the problem. He immediately popped the hood and showed me how to fix it. On the KW on the passenger side is a rubber hose descending from the air conditioning unit, just in front of the firewall. The bottom of the hose pinches in with a slit at the bottom. He squeezed the sides of the slit and at least a half gallon of water poured out. The slit is supposed to allow water to get out, but prevent dust and dirt from getting up the hose. Sometimes it gets clogged, so just squeeze the end of the hose. That dried everything up right after that. I periodically squeeze that outlet as part of my pretrip, especially in hot and humid weather.