How bad is hooking up a battery backwards to a car

Hello, installing terminals on a battery backwards is a terrible thing that can definitely cause damage to various parts of the vehicle's electrical system. When reverse polarity happens, damage happens.Fuses typically blow, for one thing, to protect certain areas. Other components aren't so lucky. Testing is needed to find out what's going on. Use this link to find some shops near you that can help with your concern: www.repairpal.com/repair-shops