Tips for looking after your car keys

5 minute read

Hand holding key to open car door

These days, many vehicles have keyless technology, meaning you can lock, unlock, and even start the ignition, all at the touch of a button. To find out how you can take care of your fob, including how to change the battery and what to do if it comes into contact with water, keep reading.

How to change a car key battery

If you notice that your car key fob only opens the doors now and again, or it does not lock or unlock the car at all, this could be a tell-tale sign that the fob battery needs replacing.

Changing the battery inside a car key fob is quick and easy for you to do at home. However, if you'd prefer, you could take it to your local garage or car dealership for assistance.

Is the battery the issue?

To determine that it is definitely the battery that’s the problem, you can first check if the manual locks on the car still work using the car key. Most car fobs have a key located inside the fob, or the key can be removed from the fob by pressing a small button or lever on the side of the fob.

If the manual locks on the car don’t work, it could be an issue with the vehicle’s locking mechanism rather than the car key or the fob battery.
If you have a spare fob for your car, you could try locking and unlocking the car with this too. If it works, you can assume that the battery in the other one needs replacing, with the most common type of car battery being the CR2032.


Accessing and replacing a car key battery

To change the battery in your key, try lifting up the part of the fob where the battery is situated using your finger, or you can also do this using a flathead screwdriver if it’s proving stiff. Then you can remove the battery.

On one side of the battery, you should be able to see a code. In most cases, this code begins with two letters, such as CR, and is followed by some numbers. If you are struggling to find the code, you should be able to find this information in your car manual.

Using this code, you’ll be able to identify the kind of battery you’ll need to purchase as a replacement. Either take this code to a suitable retail shop, such as Halfords or shop online from sites like Amazon.

Now, replace the battery and test the fob to see if it’s working correctly.

Car keys being held in front of red car


How long do car key batteries last?

You probably use your car key fob a lot more than you think. Aside from using it to lock and unlock your vehicle, it’s likely your fob offers a variety of additional features too. For example, you might also use it to open and close the boot, and you might even be able to use it to start the ignition.

With this in mind, you could find that your car key battery lasts around three to four years before it needs replacing.


How to dry out a car key fob

There’s no denying that water, and other types of fluid can be bad news for your key fob. It has the potential to damage the internal electronics of the fob, and even stop it from working altogether. So, if this happens, it’s important that you know exactly what you can do to help dry out your car key fob.

Important: if your key fob has been exposed to salt water, corrosion on any protection applied to circuits is likely from the salt and therefore the following process is less likely to work and a replacement is advised.


Step one: dry your fob

First, grab something to dry the fob with. It’s a good idea to turn the fob so that the buttons are facing downwards, giving it a gentle yet firm shake to remove as much excess water as possible. You may be concerned that you might get a shock from the wet car fob. However, it is highly unlikely that this would happen, but it is still advised to dry off the fob as soon as possible using a towel or cloth.


Step two: remove the battery

Once you’ve dried it off as much as you can, remove the battery from the fob following the instructions outlined in the first section above. After you’ve taken the battery out, don’t replace it with a new one just yet. It’s a good idea to let the inside of the fob dry out for a couple of days, especially as this is where the transmitter, and in some cases, a chip which controls the vehicle’s ignition system are located.

Top tip: to help the fob dry out as much as possible, you could place it in a plastic bag with some packets of silica gel. These small sachets are often included when you buy a new pair of shoes or a handbag, so you might want to check if you have any of these lying around your home. If you don’t, you can simply leave your fob to air dry in a warm room.


Step three: testing

Once the inside of the fob is dry, you can replace the battery and try it out to see if it works. If it doesn’t work, you will need to get a replacement key fob. In this case, it’s worth checking your car insurance policy to see if you’re covered for key protection, as you may be able to process a claim for the damaged fob and request a new one from your car dealership.

Inevitable accidents happen from time to time when it comes to car keys, whether they slip out of your pocket into a puddle or the key fob battery runs out just as you’re nipping out. Hopefully, these tips will help you next time you find yourself in need.


For more useful information on car care and maintenance, take a look at our Useful Article section.