How to Fix a Key Fob That isn't Working
If your key fob isn't working There are a few simple steps that can be taken to fix it. The first step is to be sure that it's not the backup remote.
If your backup remote is unable to unlock and lock the doors of your car, it is most likely that the primary remote is not working. Most problems with car remote keys are caused by circuitry or battery problems.
Battery
It is not uncommon for the battery inside a car key fob to get worn out. It is simple to replace a battery. However, it is important that you choose the right type. You can consult your owner's guide or contact the manufacturer to determine the correct type. It is also important to examine the battery compartment, since dead batteries can leak toxic chemicals that could damage the remote. If changing the batteries doesn't solve the problem it could be that there are other issues that require attention from a professional. For example, if buttons seem stuck or damaged It may be necessary to disassemble the remote and rework its parts. You can also try reprogramming the vehicle to recognize the new remote.
Buttons
Key fobs can get dirty and worn-out from repeated use. It is not uncommon to have buttons stop working, or to require a hefty push to make them work. This can be a huge hassle especially if you're away from home and need to start your car. Fortunately, even worn out or malfunctioning buttons can often be fixed with a little time and some of the materials you may already have around the home.
First, ensure that the batteries are up correctly and that the indentation on the back of the button is filled. Then, open the remote with care and look over the circuit board. Examine for signs of rust or other indications that the buttons are worn out or damaged, such as missing paint that is conductive. Then, using a Q-tip that has been dipped in rubbing alcohol, gently clean any membrane contacts that are damaged or have conductive paint missing. Do not rub too vigorously in order to damage the conductive paint and stop the button from firing when pressed.
Check the battery connector terminals for loose solder connections. If this is the case, soldering them back in place can restore function to the button. You can follow the same procedure to restore functionality to any other loose connection inside the fob.
In the end, if any of the buttons made of rubber on the front of the key fob have stopped functioning or require a hard press to work, it is likely that the graphite disks at 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 will bring the button back to life.
If none of these solutions work, or if you still not be able to get the button respond when pressed hard, it could be that the circuitry is failing. This can sometimes be repaired by a quick clean and replacing the solder, but it is recommended to have an additional fob in case this method does not work for you.
Circuitry
If the keys fob buttons are functioning the circuit board that is inside the remote could be dirty. A very thorough inspection is often enough to resolve this issue. Water and broken cases are the most common causes of dirty boards. car remote key repair damaged case allows water and other debris to get in and short out the electronic components. Water can also eat through pins and vias, which are small connectors that are found on the board.
If you're able to open your key fob and don't mind making a mess, we can remove the solder from the buttons and solder new ones in their place. It's also worth looking at the battery terminal connections. They can become very dirty and if they're loose the buttons may not work or even stick in their down position. Soldering the terminals back to their original positions is often enough to bring a non-working fob to a working condition.
Non-Remote Transponder Chips
The non-remote chips that are sealed are more durable than their remote fobs, however they are susceptible to cracking in the event of a hole being drilled in them or in the event that a door handle of a car or lawnmowers is pushed over them. Fuse failures are usually to blame for non-remote chip failures.
If you're not comfortable opening the key fob, you can remove the circuitboard and use a multimeter to determine if the diode is working correctly. If you're not confident doing this, go to your local hardware store or Oreilly's and they usually have an RFID frequency tester that can let you know whether the key fob transmitting a signal.
Programming
Key fobs are subject to a lot of abuse and aren't completely indestructible. They can lose their pairing to the car's receiver because of shock or a low battery, which requires them to be reprogrammed. A professional auto locksmith or main dealer can reprogram your key fob and get it working again. In the event that resetting and repairing your key fob fails, it could be time to replace it completely.