If the Direct Deposit you entered on your 2019 return hasn’t changed, you don’t need to take any action.  The account information on the return will be used to direct your stimulus payment.

However, if the account info on your return is no longer valid, you should know that the IRS has not yet published guidance for updating Direct Deposit information for stimulus relief.  

The IRS's Economic impact payments: What you need to know page indicates that "In the coming weeks, Treasury plans to develop a web-based portal for individuals to provide their banking information to the IRS online, so that individuals can receive payments immediately as opposed to checks in the mail."

Please see the FAQ How do I update my direct deposit bank account info with the IRS? in TurboTax's Everything to help you get your stimulus check as soon as possible for the most up-to-date direct deposit information. 

Hello.  If I filed my 2019 taxes with Turbo Tax and owed money to the IRS.  I set up my checking account to pay it electronically, so does that mean I'll get my stimulus check via direct deposit or will it come in the mail?  I haven't received a refund in 2 years.

No, if you had an amount due, the stimulus payment won't be deposited to your account.

The IRS plans to develop a web-based portal for individuals to provide their banking information to the IRS online, so that individuals can receive payments immediately as opposed to checks in the mail. IRS website