If you've read a vehicle service manual, you've probably noticed the first step is usually "Disconnect the negative battery terminal." This is a safety procedure; it must be done when you are working on or near vehicle electronics, fuel systems or engine components. By disconnecting the negative battery cable, you remove the "ground," shutting off power to your system. Wear goggles and gloves when working around car batteries.
Turn the engine off and remove the key from the ignition.
Open the hood and find the battery. The battery is usually located in the front, near one of the strut towers.
Remove the protective battery cover, if applicable. Many newer vehicles have plastic "lids" covering the battery.
Locate the negative battery terminal and cable. The negative terminal has a minus (-) symbol beside it; the cable is usually black.
Loosen the nut holding the cable to the terminal. Use an adjustable wrench or a pair of pliers (remember, "right-tight, left-loose").
Grasp the end of the cable near (but not on) the terminal. Wiggle the cable back and forth and up and down until it comes off.
Move the cable away from the battery terminal; incidental contact could activate the electrical system.
Replace the cable and tighten the nut when you are finished with your project or repair.
