Ok...that is the same model as in the 2008. I've installed a Dometic 2652 and worked on a couple and have never seen one, when installed with a roof vent (chimney), that had a fan. I take that back, I did "remove" a fan from a friend's refrigerator, but, he had bought his TT used and the previous owner had installed an after market fan. It, too, was making noise, so I removed it.
None of the literature I've got on Dometics show a fan as an option from the Dometic factory, unless it is something brand new for this year. I can't find a parts listing for the fan, it doesn't show in the installation details and there is no provision for a power connector on the board. If it is listed for you as "optional" it could be from anywhere and almost anyone could be responsible for fixing it...you're best bet would be to start by calling your dealer; he may have a better idea as to the source of the fan.
If the noise is bothering you, in the meantime, you could disconnect the power wire to the fan. As I mentioned, Dometic's installation requirements do not "require" a fan to function properly when installed with the proper roof vent and there are literally thousands of these 2652's out there cooling along just fine without it...
My 2 cents, your mileage may vary...
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