Les
Try
www.rvsurplussalvage.com for your part. They are located in Elkart Ind. They buy excess parts from allof the manufactures. I'm sure they have a replacement fan that will fit your ehaust vent. I have used them a couple of times and they had the parts. In their warehaouse they have replacement sofas, chairs, tables and every item that you would ever want. We went thru their place when the MOC Rally was up there a few years ago.