How to Fix a Key Fob That isn't Working
If your key fob doesn't work, a few easy steps can be taken to fix it. First, make sure that it's not your backup remote.
If the backup can lock and unlock your car doors it is most likely an issue with the primary remote. Most problems with car remote keys result from circuitry or battery problems.
Battery
It is not uncommon for the battery inside a key fob for cars to get worn out. It is simple to replace a battery. However it is crucial that you use the correct kind. You can consult the owner's manual or contact the manufacturer to inquire about the right kind. It is also important to check the battery compartment, since batteries that are not working properly can release caustic chemicals which can damage the remote. If changing the batteries does not solve the problem it could be because there are other issues that require attention from a professional. If repair broken car key are damaged or stuck, for example, it may be necessary disassemble the remote and rework each component. You could also try reprogramming your car to recognize the new key fob.
Buttons
Key fobs can get dirty and worn out from frequent use. It is not uncommon for buttons to cease functioning, or require a hard push to make them work. This can be extremely frustrating particularly if you're away from home and need to start your car. Even broken or damaged buttons can be fixed with a little time and the tools you already have at home.
First, verify that the batteries are correctly installed and that the indentation on the back of the button is filled. Open the remote carefully and look over the circuit board. Check for indications of rust or other indications that the buttons are damaged or worn out. For example, conductive paint may be missing. Then, using a Q-tip that has been dipped in alcohol to gently clean any membrane contacts that are damaged or have conductive paint missing. Avoid rubbing too hard, as this can erode the conductive paint and block the button firing when the button is pressed.
Also, carefully check the battery connector's terminals for an unattached solder connection. Soldering them back into place will allow the button to function again in the event that this is the situation. You can apply the same process to restore functionality to any other loose connection in the fob.
Finally, if any of the buttons made of rubber on the front of the key fob aren't working or require a very long press to function it is likely the graphite disks that are on the back of the button are wearing out and need to be replaced. This can be done by rubbing a pencil over the disks, which should bring the button back to its original state.
If none of this is helpful, or if the button doesn't respond to a firm press, then it may be the case that the circuit board itself is damaged. It is possible to fix this by a quick clean and replacing the solder, but it is best to have an extra fob available in the event this method doesn't work for you.
Circuitry
The circuit board in your remote control could be dirty, regardless of whether the buttons on the key fob function or not. This issue can be fixed through a thorough examination. The most common causes for dirty circuit boards is water and broken cases. A damaged case could allow water and other debris to get into the circuit board, which can cause it to short. Water can also destroy pins and small connectors on the board, which are known as via's.
If you're able to remove your key fob and aren't afraid of making a mess, we can de-solder the buttons and put new ones in their place. Also, it's worth checking the connections between battery terminals. They can become extremely filthy and if they're not tight enough, the buttons may not work or even stick in their down position. Soldering the terminals back into place is usually enough to restore a non-working fob to working.
Non-Remote Transponder Chips
The non-remote chips sealed in a sealed case are more durable than remote fobs, however they are susceptible to breaking if a hole is drilled in them or if a car door handle or lawnmowers plows over them. The failure of the fuse is usually the cause of non-remote chip failures.
If you're not comfortable opening the key fob, take the circuit board off and use a multimeter to check that the diode is operating properly. If you're not confident doing this, head to your local hardware store or the Oreilly's and they'll usually have an radio frequency tester that can determine if the key fob is transmitting a signal.
Programming
Key fobs are subject to lots of abuse and aren't indestructible. They may lose their connection to the receiver in your car due to shock or low battery, which calls for them to be reprogrammed. A professional auto locksmith or a main dealer can reprogram your key fob to get it back up and running. If, in the unlikely event that resetting or repairing your key fob isn't working it may be time to replace it entirely.