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How to change the battery in a key fob

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    A “key fob” typically refers to the plastic shell that houses the key shank (the actual metal part that goes into your door lock) and, these days, usually has buttons you can use to remotely lock and unlock the car. It’s a convenient tool for drivers to access or perhaps even start their car with a click of a button — that is, until that button stops working due to a dead battery. Let’s learn about how to change the battery in a fob, as well as go over how you might replace your key fob if you’ve lost it.

    How to replace a key fob battery

    Key fobs come in different shapes and sizes. Your car manufacturer's guidelines may include step-by-step instructions to change your key fob battery. Depending on your key fob, you might be able to change the battery yourself. Typically, key fobs are designed like a “clamshell” to include a line that splits down the middle of the fob’s profile. If your key fob looks like this, you may be able to replace the battery by:

    1. Picking up a replacement battery: Generally, the battery size you’ll need to purchase is printed along the outside of the key fob. If it is not, you may need to open the fob to determine the type of battery needed. You can likely find replacement batteries at an auto parts store or online.
    2. Opening the fob: You’ll need to open your key fob by prying open the line that runs down the middle of the fob. You may need a small tool like a flathead screwdriver or a small coin to help pry it open. If you feel like you’re at risk of damaging the key fob, you may opt to take it in for a professional replacement at your dealership instead.
    3. Checking the battery orientation: Most key fob batteries will be shaped like a small coin with a plus and minus sign marked on them. Be sure when you replace your old battery with the new one that the positive and negative orientations line up the same way.
    4. Putting the fob back together and testing: After you’ve replaced the battery, put the key fob back together and give it a test. If it’s still not working, you may need to visit your local service station to have your battery replaced professionally.

    What to do if you've lost your key fob

    Replacing a dead battery in your key fob may be inconvenient, but losing the fob altogether could be a little more troubling. Since the key fob is often the shell encasing your actual car key, if you’ve lost your key fob, chances are you need a car key replacement, too. If you didn’t lose your keys but instead simply locked them in your car, you may be able to hire a locksmith or call roadside assistance for help (provided you’re covered for it through your policy).

    Replacing your car key and key fob

    Most key fobs contain a transponder chip that’s uniquely coded to your car as a security measure. Without this chip being properly programmed, you won’t be able to start your car — even if your physical key fits into the ignition perfectly. Sadly, these keys may not be as easy to replace as a simple key cut at your local hardware store. Instead, you’ll likely need to visit an authorized dealership that has the equipment needed to cut and program a replacement key that works for your car.

    How much does it cost to replace a key fob?

    Since replacing a key fob likely means you’ll need to replace your transponder key too, you might expect the cost to rise a little more to pay for the specialized programming needed in your new key. While the total cost may depend on your car’s manufacturer, you might expect to pay anywhere up to a few hundred dollars for a replacement.

    In summary

    Losing the convenient “click-of-a-button” access to your car can certainly be frustrating. Thankfully, depending on your key fob, the process of changing the battery in a fob is often only a few steps, typically outlined in your car manufacturer’s guidelines. If you don’t feel comfortable changing your key fob battery yourself (or if you’ve lost it entirely), you can likely get a professional fix or replacement at an authorized dealership for your vehicle.

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