Yup, the sparks when you short circuit can be spectacular (the car battery can provide quite a current), but the voltage can't kill you. It would suck if it could - high voltage cables all around you would make accidents very dangerous. The worst that could happen to you is burns from the wires getting hot.
I've been in a passenger in a car that had a short in the facia while driving - the car immediately filled with dense choking smoke and we nearly crashed. Scary stuff. This wasn't recently though - I hope the standards for in-car wiring have improved a lot over the years!