Engine does not crank (bad block ground) - Cadillac

From a channel Lumen includes in full: ScannerDanner is Paul Danner, an automotive instructor, teaching electrical and engine diagnostics on real cars with scope and meter readings, showing the reasoning behind every test.

A 17-minute video from ScannerDanner's catalogue; the title names its topic.

Video by ScannerDanner, played through YouTube's embedded player.