How to Fix a Key Fob That isn't Working
If your key fob does not work and you're not sure why, you can fix it with just a few steps. The first step is to make sure that it's not the backup remote.
If the backup is able to lock and unlock your car door, then there is likely an issue with the main remote. The most common causes of car remote key failure are issues with the circuitry or battery.
Battery
It is not unusual for the battery in a car key fob to wear out. It is quite simple to change out the battery, however it is important to make sure that you choose the correct type; you can look in your owner's manual, or contact the dealer of the manufacturer to determine the type of battery you require. It is also essential to inspect the battery compartment, as batteries that are not working properly can release toxic chemicals that could damage the remote. If changing the batteries does not solve the problem, it may be that there are other issues that require attention by a professional. If the buttons are broken or stuck, for example it might be necessary to disassemble the remote and rework each component. You can also try reprogramming the vehicle to recognize the new key fob.
Buttons
Key fobs may become dirty and worn out from frequent use. This is not atypical, but it can cause buttons to cease functioning or require a long press to work. key repair can be extremely frustrating, especially if you are away from home and need to start your vehicle. Fortunately, even worn out or broken buttons can usually be fixed with just a bit of time and some of the materials you have in the home.
First, check that the batteries are properly charged and that the indentation on the back of the button is filled. Then, carefully open up the remote and examine the circuit board. Look for signs of corrosion or other signs that the buttons are worn out or damaged, such as missing conductive paint. Use a Q-tip, dipped in rubbing alcohol to gently clean any membrane contact that has worn-out or where conductive paint is missing. Be careful not to rub too hard, because this could damage the conductive paint and block the button from firing when it is pressed.
Also, carefully check the battery connector terminals for any loose solder connections. Soldering them back in place can restore the button's functionality if this is the situation. You can use the same method to restore functionality to any other loose connection within the fob.
Finally, if any of the buttons made of rubber that are on the front of the key fob stop working or require a long press to function, it is likely that the graphite disks on the back of the button are wearing out and need to be replaced. You can do this by rubbing a pen across the disks. This should bring the button back to life.
If none of these solutions work or you not be able to get the button respond when pressed hard, it is possible that the circuitry has failed. It is possible to fix this issue by cleaning and re-soldering your fob however, you should have a spare in case it doesn't work.
Circuitry
Whether or not the keys fob buttons are functioning the circuit board that is inside your remote might be dirty. A very thorough inspection is usually enough to fix this problem. The most common causes of dirty circuit boards is water and damaged cases. A broken case allows water and other debris to pass through and short out the electronics. Water can also destroy pins and small connectors on the board called via's.
If you're able to open your key fob, and you don't mind making some mess, we can take the buttons out of their sockets and solder in new ones. It's also worth looking at the battery terminal connections. They can become very dirty and if they're loose the buttons might not function or even stay in their down position. Soldering terminals and buttons back to their proper positions is usually enough to return a malfunctioning 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 in the event of a hole being drilled in them, or when a door handle for a car or lawnmowers plows over them. Most of the time non-remote transponder chips fail, and this can be attributed to blowing fuses.
If you're not comfortable opening the key fob, remove the circuitboard and utilize a multimeter to verify that the diode is operating properly. If you don't feel comfortable with this, go to 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 are subject to lots of abuse and aren't completely indestructible. They can lose their pairing with the receiver inside your vehicle due to shocks or low battery, requiring reprogramming. A professional auto locksmith or dealer can reprogram your key fob and get it functioning again. If resetting or fixing the keyfob is not working, you may need to replace it.