If you are using your timeshare for purely personal purposes then the maintenance fee is not deductible. If you rent out your timeshare to others for an income motive then you may be able to deduct this as a rental expense.
Otherwise, only mortgage interest and property taxes are deductible. To be deductible, the loan must be secured by the property.
Please feel free to post any additional details or questions in the comment section.
I rented one week with Worldmark's program and received a 1099-misc. Can I claim income/expenses without doing the additional schedule for rental property since I own the time at the resort not actual location they chose?