Why Do You Disconnect The Negative Battery Terminal First. By removing the negative battery cable you are disconnecting the battery from the chassis of your vehicle. The grounded terminal should be disconnected first to ensure that a battery dead-short does not occur should the spanner disconnecting the other one contact a nearby grounded metal part.
You can do this by loosening the clamps that put the failing battery terminal ends in place. Clean any corrosion off of the battery and terminals with a can of spray-on battery cleaner. Clean the battery posts and terminals with the post and terminal cleaning.
Positive current on the other hand flows into the circuit from your battery.
A battery disconnect switch is strategically placed between the negative battery terminal and the cable. If you were to leave both cables hooked up your car would likely be dead after about 2 to 4 weeks due to parasitic draw. Your vehicles electrical system is a closed circuit. A battery disconnect switch is strategically placed between the negative battery terminal and the cable.
