The best you can get for the dependent is a $500 credit against federal taxes owed ... so there must not be any tax to negate as the credit is not refundable. May I suggest you look at the form 1040 before and after you enter the dependent to see how it affects (or doesn't affect) the return.
You can peek at only the Federal form 1040 and the summary of the state info by going here:
1) lower- Left side of the screen...click to the left side of the "Tax Tools" text selection.
2) then select "Tools"
3) then select "View Tax Summary" from the pop-up
4) then back to the left-side and "Preview 1040"
Then hit the "Back" on the left side to get back to your tax entries.
To view your entire return using the online editions (including the state) before you file, you will need to pay for your online account.
To pay the TurboTax online account fees by credit card, without completing the 2019 return at this time, click on Tax Tools >>> Tools and then Print Center. Then click on Print, save or preview this year's return. On the next page, to pay by credit card, click Continue. On the next screen it will ask if you want Audit Defense, if you do not want this option just click on the Continue button. The next screen will ask for all your credit card information so you can pay for the account.