Safety First You should consider all safety risks before performing any basic maintenance or repair on your car. If the battery terminals are dirty, wipe them off with a rag or wire brush. Depends on engine speed. Right away, the electrical systems should activate. Not Helpful 1 Helpful 7.
Both cars should be turned off, with keys removed.
How to Jump Start a Car Battery
Another dead car battery? I always got confused about which car I should disconnect first. Take just a moment to visually inspect your car battery. Finally, consider whether the problem is your alternator. Instead, attach that clamp to an unpainted, metal part of the car, such as a shiny, clean nut on the engine block.