Did you try this?
If your RV qualifies as a 2nd home, you can deduct the mortgage interest without a 1098:
1. With your TurboTax open, choose Deductions & Credits
2. Under Your Home, Choose Mortgage Interest and Refinancing (Form 1098) (Choose this even if you don't have a 1098)
3. Answer Yes to Did you pay any home loans in 2022.
4. On the next screen, enter your Lender's name
5. Choose "The Seller is financing this loan and we didn't receive a 1098" then continue through the prompts and questions for this section. (You will need to enter the lenders EIN or social security number, as well as some other information to continue)
Please see TurboTax Expert PattiF's original answer to a similar question here.
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