To replace an automotive battery cable, disconnect the old one from both ends, and install the new one the same way. Both cables attach to the battery, but the positive cable leads to the starter and the negative cable secures to the engine block.
To replace an automotive battery cable, first disconnect the negative cable at the battery to avoid getting shocked. It's usually black and identified by a negative sign at its terminal. Use the correct wrench to loosen the connection, and pry the cable upward with a flat screwdriver.
Next, disconnect the positive cable at the battery. It's usually red and identified by a positive sign at its terminal. If there's excessive corrosion at the terminal, you may have to clean it to loosen it up. Use a screwdriver to gently pry it upward.
If removing the negative cable, trace it to the area on the engine block where the other end connects. Use the proper wrench to loosen the mounting bolt, and disconnect the cable. Set aside any plastic retainers used to secure the cable before removing it.
If removing the positive cable, trace it down to the starter. You may have to get beneath the vehicle to access this area. Use the proper wrench to loosen the retaining nut. Remove any plastic retainers before pulling the cable out.
Before installing the new cable, line it up with the old one, and make sure they're the same length. Then connect the end that goes to either the starter or engine block. Lay the cable along the same route as the original one, replacing any retainers. Make sure to connect the positive cable to its terminal first, followed by the negative cable.