With the fender, hood and front grill of this Cirrus removed, the wheelwell-mounted battery, HOT cable and jumper terminal connection are visible.

Part 1 of this series addressed vehicle battery locations. Part 2 presented step-by-step guidelines for total shutdown of a vehicle’s electrical system. We’ll now discuss what to do when you raise the hood to shut down the electrical system and don’t find a battery.

If no battery is visible in the engine compartment when you raise the hood, you should immediately look for decals or labels indicating the location of the positive (red) and a negative (black) terminal connection. These decals with the plus (+) and minus (–) sign and the words “Positive” and “Negative” help locate these cable terminals. They are provided by the automaker to facilitate jump starting a vehicle when the battery is not within the engine compartment area.

After running through a hole in the wheelwell, the HOT cable attaches directly to the terminal. Note the ground cable and terminal at the upper right of the photo.

DaimlerChrysler’s Stratus, Cirrus and Breeze vehicles, for example, have their battery located within the driver’s front wheelwell. General Motors’ Oldsmobile Aurora and Buick Riviera have their battery under the rear seat cushion. It would be extremely difficult to connect jumper cables to the actual battery on these vehicles, so the remote terminal connections are provided and labeled under the hood. By locating this terminal and cutting or disconnecting the battery cables, firefighters can completely shut down a vehicle’s electrical system without ever getting to the battery itself.

What if I told you that there are vehicles with their battery in the trunk that also have an automatic electrical system shutdown? On some BMW models, the battery is inside the trunk on the extreme right side of the vehicle. BMW has a feature available on newer models called the “Safety Terminal.” The Safety Terminal feature is on the red battery cable and can be identified by a large metal sleeve on the cable near the positive post of the battery.

The battery of this Volvo S80 sedan is under the floor of the trunk. The large cable at the top of the photo runs to the engine compartment.

At the instant, the frontal airbags deploy on these late-model BMWs, the explosive charge of the Safety Terminal separates the hot cable inside the thick black sleeve. This action shuts down power from the battery to the starter in the engine compartment. The vehicle however, remains energized with 12 volts of electrical power. Upon airbag deployment, the BMW automatically turns on its four-way flashers, pops electric door locks to the unlock position and turns on the dome light.

If you raise the hood on a crash-damaged BMW and do not find a battery, open the trunk, then open the battery compartment along the right side of the trunk. You can then cut or disconnect both battery cables to assure total electrical system shutdown. It doesn’t matter whether there is a Safety Terminal feature; attack the battery to accomplish a complete electrical system shutdown.

Total electrical system shutdown on the Volvo S80 can be accomplished by disconnecting or cutting the cables under the red terminal connector along the firewall area.

Mercedes, Jaguar and Volvo are three examples of other manufacturers who place their batteries inside the trunks of their vehicles.