The credit is non-refundable, which means you can't get paid if the credit is more than your tax liability. But that's not the same as a refund. For example, if you paid $10,000 in withholding on your pay checks and get a $2000 tax refund, then your tax liability was $8000. If the same person had only $7,000 of withholding and owed $1,000 on April 15, their tax liability is still $8,000. Your tax liability is shown on line 16 of the 2019 form 1040. As long as the liability is more than the credit, the credit will be fully refunded to you in the year you bought the qualifying vehicle. If the credit is more than your liability, it will be refunded up to your liability and the rest will carry forward to the next year is lost. (Some credits carry forward, this one does not.)
