Well, upon further searching, I found a little more info, but really not step by step info on how and what is needed to repair this.

I even found a couple of old posts of mine from back in 2006 when I was having this issue on my old 380SE.

I did read where someone recommended closing the center dash vents if some air was coming out there and it is on my car, so we may try that for now and see if its sufficient for her. We may end up taking it to a MB shop somewhere and get this repaired if it dont cost a fortune.