Your vehicle's battery is one of the main components of your vehicle's electrical system. When the battery fails in your vehicle, it can cause a non-starting condition, stalling or even transmission issues. All of these symptoms are temporary, and they go away as soon as you replace the battery. When installing a battery, there is a specific order that must be followed when disconnecting and connecting the battery cables, to lessen the chances of shorting out the vehicle's electrical system.
The entire electrical system in your vehicle leads back to the battery at one point or another. This is why a minor short in the battery may result is electronic failures in other areas of the battery.
When disconnecting a battery, you are in direct risk of creating a short at the heart of your vehicle's electrical circuit. While you are loosening the bolt or nut that secures the positive cable to positive terminal of the battery, you will likely touch a metal part of the vehicle. The negative battery connects directly to the vehicle's body, and this can potentially short out the battery. This is why you always want to disconnect the negative cable first, as it eliminates the battery's ground to the vehicle's body.
When reinstalling the battery, the same principles of circuitry apply. In this case, you want to install the positive cable first, so that you do not mistakenly ground the battery by touching the vehicle's body, which can cause a short in the battery. After securing the positive cable on the battery, you can then install the negative cable.
When you create a short in the electrical system, the results can be minor or severe. A minor short will typically result in one or more blown fuses. If you create a major short, such as when touching the bare body metal near the ground, you may cause the battery to explode, causing severe harm to yourself and the vehicle.
