The sales tax deduction will not change your refund unless your total deduction for state and local taxes is less than $10,000 ($5,000 if married filing separately) and your total itemized deductions are more than your standard deduction.
Under the new tax law, for 2018 through 2025, the deduction for state and local taxes is limited to a maximum of $10,000 per year ($5,000 if you are married filing separately). The maximum applies to the total of real estate tax, personal property tax, and either state and local income tax or state and local sales tax. The new law also made the standard deduction much higher, so your total itemized deductions might have been more than your standard deduction before 2018, but are now less than the increased standard deduction.
