The Electric Vehicle Credit is a non refundable credit. This means that it can take your tax liability down to $0, but not less than $0. Once that number hits $0, there is no further benefits from any additional non-refundable credits.
If you look at your 1040 line 16, you will likely see that the number is $0. If you remove your Electric Vehicle, that number would change back to $2,900.
You can view your 1040 by clicking the following:
So how do I benefit for buying a $39,000 electric car ?
my understanding my rebate above and beyond my tax return was 6464 for the car purchase
are you telling me to remove the line if it says 2900?
because that’s all my taxes changed for my return when I added my car
Not sure what you mean by removing the line if it says 2900. Look on line 16 of your form 1040. That is you tax liability and is the maximum amount of electric car credit you can get. You may not be able to get that much if you have refundable credits such as child tax credit that further reduce you tax liability before the electric car or other NON refundable tax credit can be applied.