A: It is good to always do visual inspections on the whole length of battery cables to check if there is any burnt or cracked insulation, corrosion and other damages. Also visually inspect the cable-to-terminal connections at their ends for any form of damage such as broken wire strands, cracks or corrosions. When replacing cables, always remove the negative cable first and attach it lastly. For example, batteries in an engine compartment require disconnection of a negative cable from either the engine block / body and positive cable from a starter solenoid. For example, under seat batteries entail removing rear seat cushion and disconnecting negative cable from battery terminal, body harness and floor pan. Positive cables are connected at positive terminal of battery as well as its negative post, fuse/relay box along with front fuse/relay box too. In order to install new cables clean threads with a corrosion inhibitor or petroleum jelly can assist you do this job easily. Before attaching the cable tightly ensure that it will reach without stretching to touch the battery end.