Mercury Cougar electrical failure after stereo installation, car won't turn over on Mercury Cougar

Some Mercury Cougar owners report experiencing electrical issues after installing a stereo, including the car not turning over. These problems can stem from incorrect or insecure wiring connections related to the stereo installation, which may lead to electrical failures. Additionally, some owners find that damage to the battery or alternator during the installation process can prevent the vehicle from starting. Specifically, owners of the 2000 Mercury Cougar with a 2.5L V6 engine may encounter issues if the battery cable is misrouted, causing it to rub against the power steering line. If these troubleshooting steps do not resolve the issue, it is advisable to seek assistance from a professional mechanic or auto electrician for an effective diagnosis and repair.