Where do I find the AMT prior car depreciation amount which I need to complete 2024 tax return. Is it on my 2023 tax return, Form 4562, Part V, 26H? Or where?

If you used TurboTax last year, look for the AMT Depreciation Report. This is a TurboTax worksheet, not an IRS form. The total prior AMT depreciation is the sum of Prior and Current depreciation from that report. Form 4562 reports only regular depreciation.

Most other tax software produces a similar report, one each for regular and AMT depreciation.

generally for a vehicle placed into service in 2023 the AMT depreciation will be the same as the regular depreciation.

If there is no Form 6251 for AMT in your return last year, the amount would be the same as regular depreciation.