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. The first step is to be sure that it's not your backup remote.
If the backup can lock and unlock your car doors, then there's a likely issue with the main remote. The most common causes of car remote key failure are issues with the circuitry or battery.
Battery
The battery inside a key fob can wear out over time. It is easy to replace batteries. However it is crucial to select the right kind. You can refer to the owner's manual or contact the manufacturer to determine the correct type. It is also a good idea to examine the battery compartment with care since dead batteries may leak harmful chemicals that can damage the remote. If replacing the battery does not fix the problem, there may be other issues that require professional attention. If repair car key fob are damaged or stuck, for example it might be necessary to take the remote apart and rework each component. You can also try reprogramming your car to recognize the new key fob.
Buttons
Due to frequent use, key fobs could wear out and become dirty. This is not uncommon however, it can cause buttons to cease working or require a very long press to work. This can be very frustrating particularly if you're away from home and need to start your vehicle. Even malfunctioning or worn-out buttons are often fixable with a bit of time and the tools you already have at home.
First, make sure that the batteries have been correctly inserted and that the indentation at the back of the button is filled. Take the remote apart and look over the circuit board. Look for signs of corrosion or other signs that buttons are worn out or damaged, such as missing conductive paint. Use a Q-tip, dipped in alcohol to gently clean any membrane contact that has become damaged or where conductive paint is missing. Do not rub too vigorously in order to damage the conductive paint, and block the button from firing when pressed.
Also, make sure to inspect the battery connector's terminals to ensure any loose solder connections. If this is the case, connecting them back could restore functionality to the button. The same method can be used to restore functionality to any other loose connections in the fob.
If any of the rubber buttons at the front of the keyfob isn't working or need to be pressing extremely hard the graphite disks on the back of the button might have worn out and need to replaced. This can usually be done by rubbing a pencil over the disks, which should bring the button back to life.
If none of these solutions work, or if you still cannot get the button to respond when you press it hard, it could be that the circuitry has failed. It is possible to fix this issue by cleaning and re-soldering your fob but you should also have a spare in case it doesn't work.
Circuitry
The circuit board inside the remote control could be dirty regardless of whether the buttons on the key fob function or not. A very thorough inspection is usually enough to fix this problem. The most common causes for dirty circuit boards are water and damaged cases. A damaged case can allow water and other debris to enter and short circuit the electronics. Water can also damage pins and vias, which are the tiny connectors on the board.
If you're handy enough to open up your key fob and don't mind a little mess, we can take off the buttons and then solder new ones in their place. It's also worth looking at the battery terminal connections. If they are loose, the buttons may not work or even become stuck in their down position. Soldering the terminals and buttons back into place is typically all that's required to return a non-working key fob to functioning condition.
Non-Remote Transponder Chips
Sealed non-remote transponder chips are more durable than the remote fobs that contain them but they can be cracked by a hole made in them or pushed over by a lawnmower or door handle for a car. Most of the time non-remote transponder chip malfunctions could be attributed to an exploded fuse.
If you're handy enough to open up the sealed key fob and are willing to put up with the mess, you can easily remove the circuit board and test the fuse with a multimeter for proper diode function. If you're not comfortable doing this, go to your local hardware store or Oreilly's and they'll usually have a radio frequency tester that can determine whether the key fob transmitting a signal.
Programming
Key fobs are subject to lots of abuse and aren't impervious to damage. They may lose their connection to the car's receiver due to shock or a low battery, requiring the reprogramming. A professional auto locksmith or main dealer can reprogram your key fob and get it working again. In the event that resetting and fixing your key fob isn't working it may be time to replace it all over again.