How to Fix a Key Fob That isn't Working
If your key fob does not work, you can fix it with just a few steps. First, make sure that it's not your backup remote.
If the backup is able to lock and unlock your car doors then there's a likely issue with the primary remote. Most car remote key failures are caused by battery or circuitry problems.
Battery
The battery in the key fob may be worn out over time. It is easy to replace the battery. However it is crucial to select the right type. You can consult your owner's guide or contact the manufacturer to inquire about the correct type. It's also a good idea to inspect the battery compartment thoroughly, as dead batteries sometimes leak harmful chemicals that can cause damage to the remote. If replacing the batteries doesn't solve the problem it could be that there are other issues that require professional attention. For example, if buttons seem to be stuck or broken it could be necessary to disassemble the remote and rework its components. You can also try reprogramming the vehicle to recognize the new fob.
Buttons
Due to frequent use, key fobs could wear out and become dirty. This is not uncommon, but it can cause buttons to cease working or require a difficult press to get them to function. This can be frustrating particularly when you're away from home and need to switch on your car. Fortunately, even worn out or malfunctioning buttons can often be fixed with just a bit of time and a few items you have in the home.
First, check that the batteries are up correctly and that the indentation on the back of the button is filled. Then, carefully remove the remote and examine the circuit board. Check for indications of rust or other indications that the buttons are damaged or worn out. For instance there could be conductive paint missing. Utilizing the Q-tip, dipped in alcohol to gently clean any membrane contacts that are worn or have conductive paint missing. Do not rub too vigorously as this can damage the conductive paint and stop the button from firing when it is pressed.
Also, make sure to inspect the battery connector's terminals for an unattached solder connection. Soldering them back into place will restore the button's functionality If this is the case. You can use the same process to restore functionality to any other loose connection inside the fob.
If any of the rubber buttons at the front of the keyfob isn't working or require being pressed extremely hard, the graphite disks at the back of the button might have worn out and require replacement. This is usually done by rubbing a pencil over the disks, which should bring the button back to its original state.
If none of this is useful, or if the button still doesn't respond to a hard press It could be that the circuit board has gone bad. It is possible to fix the issue by cleaning and re-soldering the button however, you should have an extra in case it does not work.
Circuitry
The circuit board in the remote control could be dirty regardless of whether the buttons on the key fob are working or not. key fob repair service is usually enough to fix this issue. Broken and damaged cases are the most common causes of dirty boards. A damaged case can allow water and other debris to enter the circuit board, causing it to short. Water can also damage pins and connectors that are small on the board, which are known as via's.
If you're able to open up your key fob and aren't afraid of a little mess, we can de-solder the buttons and then solder new ones in their place. It's also worth examining the battery terminal connections. They can get very dirty and if they're loose the buttons might not function or may even remain in their down position. Soldering the terminals and button's back in their place is generally all that's needed to return a non-working key fob to working order.
Non-Remote transponder chips
Sealed non-remote transponder chips are more durable than the remote fobs that have them but they can be cracked by a hole that is drilled into them or over by a lawnmowers or door handle for a car. The majority of non-remote transponder chips fail, and this can be attributed to an exploded fuse.
If you're handy enough to remove a sealed non-remote key fob and can tolerate the mess, you can take off the circuit board and examine the fuse using a multimeter for proper diode function. If you're not sure with this, you can visit your local Oreilly or hardware store and test their RF frequency tester. This will inform you whether the key fob is sending an RF signal.
Programming
Key fobs take a lot of abuse and aren't impervious to damage. They may lose their connection with the receiver in your vehicle because of shocks or a low battery, requiring changing the program. A professional auto locksmith or main dealer, can reprogram your keyfob and get it working again. In the rarer case that resetting or repairing your key fob fails it could be the time to replace it all over again.