How to Fix a Key Fob That isn't Working
If your key fob isn't functioning, a few easy steps can fix it. The first step is to make sure that it's not the backup remote.
If your backup remote cannot unlock and lock the doors of your car, then it is likely that the primary remote is not working. The most common causes for key malfunctions for car remotes are issues with the circuitry or battery.
Battery
The battery in the key fob may wear out over time. It is simple to replace batteries. However, it is important to select the right type. You can consult your owner's guide or contact the manufacturer to inquire about the right kind. It's recommended to examine the battery compartment thoroughly since dead batteries may leak caustic chemicals that can harm the remote. If replacing the battery does not fix the issue, there may be other issues requiring professional attention. For instance, if the buttons appear stuck or broken it could be necessary to take the remote apart and rework its components. You can also try reprogramming the vehicle to recognize the new remote.
Buttons
Through frequent use, key fobs could wear out and become dirty. It is not uncommon for buttons to cease working, or to require a hefty push to make them work. This can be frustrating especially when you're away from home and you need to switch on your car. Even malfunctioning or worn-out buttons can be fixed with a little time and the tools you already have at home.
First, ensure that the batteries are properly charged and that the indentation on the back of the button is filled. Then, carefully open up key car repair and inspect the circuit board. Check for signs of corrosion or other indications that the buttons are worn or damaged, such as missing the conductive paint. Then, using a Q-tip that has been dipped in rubbing alcohol, gently clean any membrane contacts that are worn or where conductive paint is missing. Don't rub too hard as this can damage the conductive paint and stop the button from firing when you press it.
Check the battery connector's terminals for loose solder connections. Soldering them back into place will allow the button to function again in the event that this is the case. The same process can be used to restore function to any loose connections inside 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 at the back of the button may have worn out and will require replacement. This is usually done by rubbing a pencil over the disks. This should bring the button back to its original state.
If none of this is useful, or if the button does not respond to a hard push, then it may be that the circuit board has gone bad. It is possible to fix the issue by cleaning and re-soldering your fob however, you should have an extra in case it does not work.
Circuitry
The circuit board of your remote control could be dirty, regardless of whether the buttons on the key fob function or not. A thorough examination is often enough to resolve this problem. Water and broken cases are the most frequent causes of boards that are dirty. A damaged case allows water and other debris to pass through and short circuit the electronics. Water can also get through pins and vias, which are small connectors found on the board.
If you're skilled enough to open your key fob, and aren't afraid of making a mess, we can remove the buttons from their sockets and put in new ones. It's also worth looking at the battery terminal connections. They can get very dirty and if they're loose, the buttons may not work or may even remain in their down position. Soldering the terminals, and putting the button back in place is usually all that's required to return keys that are not in functioning condition.
Non-Remote transponder chips
The non-remote chips sealed in a sealed case are more durable than remote fobs, however they can be cracked when a hole is made in them, or if a car door handle or lawnmowers plows over them. Failures of the fuse are typically to blame for non-remote chips failures.
If you're not comfortable opening the key fob, you can take the circuit board off and use a multimeter to check that the diode is functioning correctly. If you're not comfortable doing this, go to your local hardware store or Oreilly's and they'll usually have an radio frequency tester that can tell you whether the key fob is sending signals.
Programming
Key fobs aren't impervious to destruction and are susceptible to damage by a lot of things. They can break their connection with the receiver inside your vehicle due to shocks or low battery, requiring reprogramming. A professional auto locksmith, or the main dealer can reprogram the key fob and get it back working again. If resetting or replacing the keyfob is not working, you may need to replace it.