Incorrectly connected jumper cables can cause serious issues with either car and can cause potential injury or harm to you as well. You are transferring a lot of power from one battery to the other, and in the process, there are always risks involved. Incorrectly connecting the clamps can cause the polarity of the electrical system to reverse which can damage the sensitive electronic components of your engine. If you don’t feel confident jumping your own car, call roadside assistance for professional help.