A: Periodically inspect the entire length of each battery cable for damage, cracked or burned insulation, and corrosion. Poor battery cable connections can cause starting problems and decreased engine performance. Check the cable-to-terminal connections at the ends of the cables for cracks, loose wire strands, and corrosion. The presence of white, fluffy deposits under the insulation at the cable terminal connection is a sign the cable is corroded and should be replaced. Check the terminals for distortion, missing mounting bolts or nuts, and corrosion. If only the positive cable is to be replaced, be sure to disconnect the negative cable from the battery first. Disconnect and remove the cable, making sure the replacement cable is the same length and diameter. Clean the threads of the Starter or ground connection with a wire brush to remove rust and corrosion, and apply a light coat of petroleum jelly to the threads to ease installation and prevent future corrosion. Attach the cable to the starter or ground connection and tighten the mounting nut securely. Before connecting the new cable to the battery, make sure it reaches the terminals without having to be stretched. Connect the positive cable first, followed by the negative cable, and tighten the nuts. Apply a thin coat of petroleum jelly to the terminal and cable connection.