As the years have passed by, automobiles have become much more complex. What was once large and simple is now compact and complicated. Changing a battery in your vehicle was once no more difficult than keeping a couple of wrenches in the glove compartment. Today’s vehicles are a different story. What used to be as simple as a couple of wrenches could now take an entire tool box and a few hours of time if you’re not absolutely sure of what you’re doing. Since a little knowledge can go a long way, we’ll give you a few tips on how to change a car battery, in case you’re ever in the unfortunate circumstance of turning your car key on and finding everything else is off.
There was a time when “What side is it on?” was the only question you needed to ask to find a vehicle’s battery location. Batteries can now be found in fender wells, under wiring harnesses and fluid reservoirs, in trunks, and under back seats. The best place to find your battery’s location would be in your owner’s manual. However, if you are without your original owner’s manual, you can also find the information at your local dealership or online at the manufacturer’s website. The battery locations and amount of “added” removal necessary will vary by vehicle. Some mid-2000 models ofand nearly required the removal of a tire to get the battery out from inside the fender well. Some of the air-cooled Volkswagens had them in the trunk; BMW and Mercedes-Benz followed suit with the trunk idea in their models; GM placed a few under back seats and under washer fluid reservoirs; and, there are some vehicles which seem to have swallowed them completely.
Knowing the battery location will give you a decent idea of the tools you’ll need for the job. A good rule of thumb would be to simply take Tim “The Tool-man” Taylor’s advice: There’s no such thing as too many tools. Again, check your owner’s manual for the specific location and always make sure you’ve properly checked the vehicle to make sure the battery is indeed the problem, before you begin. If the battery does turn out to be faulty, the first thing to be certain of is that you have vehicle’s ignition off, preferably with the key completely removed for safety’s sake.
After finding your dead cell, you’ll want to remove one of the battery cables, and it definitely does matter which one is removed first. The negative (black) cable is the first thing to come off. Depending on whether your battery is top-mount or side-mount will determine what tools you’ll need to remove the cable. Mostly this can be done with wrenches in common sizes like 5/16”, 1/2”, and 10mm or 12mm. Do not touch anything metal to the positive terminal of the battery if both cables are still connected. This is not only for your own safety (12 volts may not seem like much, but the thousands of volts coming from the ignition coil could do some serious damage), but for the safety of your vehicle as well. Even the smallest spark from the positive terminal could cause electrical problems in the vehicle’s circuit boards. Once the negative cable is off and pulled away from the battery, you can safely remove the positive (usually red) cable the same way.
After the cables are off you’ll need to remove the battery hold-down. The hold-down usually consists of a metal bar running across the top of the battery or a small rubber or plastic wedge holding down the lip on the bottom of the front of the battery. The hold-downs can be removed with socket wrenches and extensions (some of the most common sizes you’ll need in this area are 8mm, 10mm, 12mm, ¼”, ⅜”, and ½”, but this by no means covers the array of vehicles out there). Some of the hold downs have what are called J-hooks. These are long metal J-shaped rods which latch into a small hole in the battery tray and hold the battery secure. These are removed along with the top hold-down bracket. There are other variations of hold-downs but most of them are fairly self-explanatory.
After the hold-down bracket is gone the battery should be unsecure, and you can now remove it from the vehicle. Remember to dispose of vehicle batteries properly by returning them either to where you purchased your battery for a core credit, or to an automotive repair or parts facility that accepts battery cores. Installing the new battery is the reverse procedure of removing it, just remember that the wires are installed in the opposite order of removal – positive first, negative last. And please remember that not all vehicles were meant to be worked on out in your garage. If you happen to own a hybrid or all-electric vehicle, please do not attempt any repair or removal of anything electrical on the vehicle, especially the batteries. They are far more powerful and should only be handled by trained automotive technicians.