Rotten smell coming from AC

I have a 2005 Sebring Sedan. There is a rotten smell coming out of my car vents. It happens with or without AC running. But when it is running the smell goes away after a little while and then comes back if it is turned off and then on again. From reading other posts , someone said to open the AC vent cover and wipe down the A.C. intake. I have a Chrysler Sebring, where is the AC intake and how do I access it? :1zhelp: