Add the sales taxes on your used motor home to any other sales taxes you paid during the year. Support the deductions with receipts.
File your income taxes using IRS Form 1040. The deduction for the sales taxes on your used motor home is an itemized deduction, so you cannot use any other form.
Enter the amount of sales taxes paid, including the sales tax on your used motor home, on line 5 of Schedule A.
Check the box next to line 5b to indicate to the IRS that you claimed sales taxes rather than state and local income taxes as a deduction.
Total your itemized deductions, including your used motor home sales taxes, and record the sum on line 29 of Schedule A and line 40 of Form 1040. This total replaces your standard deduction.