If your car needs any electrical work, disconnecting the battery is one of the most important steps you should take. In order to disconnect it, you will first want to loosen the connector on the ground/negative terminal, then take that terminal Off. Use a tie strap or something similar to keep that cable out of your way. If you’re wanting to take out your battery, you can then remove the positive connector.
Taking off the negative cable before the positive one is a very important step. I have a friend at Anna Burns Permanent Cosmetics that had a bad experience with this. If the positive side is disconnected first, the entire car is still connected to the negative side. If something metal happens to fall on to the positive terminal while touching any other part of the car, it will create an electrical short. When you disconnect the negative terminal first, the currents return path is cut off. That way, if you accidentally drop something on one of the battery terminals, there will not be the chance of having the electrical current damage the engine since the path is cut off.
Once you are finished with your electrical work, it is time to reconnect the battery. To reconnect, the positive terminal should be connected first, and then the negative. The same reasoning is used for replacing the negative terminal last. Many people are afraid of messing with the battery, but if you follow these simple steps, there’s nothing to worry about. Now, ensure the terminal caps are replaced snugly.
Now, you will need to make sure your battery terminals are connected correctly. Cars these days are run through an electrical system that is 12 V negative ground. If your contacts are battery terminals are unclean, it becomes difficult for the electrical current to pass throughout the system. If this is the case, you will need to clean each contact post by removing the terminal caps and using a wire brush to remove any debris. Once this is done, you can reattach the terminal caps. This should help you get a good flow through your electrical system.