Check the archives, there is the part number for a fan you can get at RV World that is much quieter.

On Jun 25, 2007, at 10:32 AM, John Graham wrote:

I pulled the whole Dometic unit out to check it when it was new to me, but I
don't remember the details of the fan.  I'm pretty sure it's a 12v model.
Has anyone replaced theirs with a quieter model from Radio Shack or other
places?  I'd like to have a new fan unit on hand before I dive into the
fridge removal again.