If you itemize deductions on your federal return, you can choose to deduct state and local income taxes OR you can deduct sales taxes. But not both. And if you are taking the standard deduction, you can't deduct either. TurboTax will choose the larger deduction, by default.
Are you working on the federal or a state return? If a state, which state?
Which deduction should I choose, state and local income tax or sales tax?