How to Fix a Key Fob That isn't Working
If your key fob doesn't work There are a few simple steps that can be taken to fix it. First, check to make sure it's not the backup remote.
If the backup can lock and unlock your car doors, then there is likely an issue with the main remote. The most frequent causes of key problems with your car remote are battery or circuitry issues.
Battery
The battery in the key fob may get worn out over the course of time. It is simple to replace batteries. However it is essential that you use the correct kind. You can consult your owner's manual or call the manufacturer to find out the right type. It is also essential to inspect the battery compartment as dead batteries can leak caustic chemicals which can damage the remote. If changing the battery doesn't fix the problem there may be additional issues requiring professional attention. For instance, if buttons appear stuck or damaged it could be necessary to disassemble the remote and rework its components. You can also try reprogramming your vehicle to recognize the new key fob.
Buttons
Through repeated use, key fobs could wear out and become dirty. This is not unusual however it can cause buttons to stop functioning or require a hard press for them to work. This can be a huge hassle, especially if you are out of town and need to start your vehicle. Even malfunctioning or worn-out buttons can be fixed with a bit of time and materials you already have at home.
First, check that the batteries are charged correctly and that the indentation on the back of the button is filled. Open the remote carefully and look over the circuit board. Look for indications of rust or other indications that the buttons are damaged or worn. For instance there could be conductive paint missing. Then, using a Q-tip dipped in rubbing alcohol, gently clean any membrane contacts that are worn or have conductive paint missing. Avoid rubbing too hard as this can erode the conductive paint and stop the button from firing when it is it is pressed.
Also, carefully check key fob repair service to ensure any loose solder connections. If this is the case, soldering them back in place could restore function to the button. The same procedure can be used to restore function to any loose connections within the fob.
If, for instance, any of the buttons made of rubber that are on the front of the key fob have stopped working or require a difficult press to function it is likely that the graphite disks at the back of the button are deteriorating and require replacement. This can usually be done by rubbing a pencil over the disks, which should bring the button back to life.
If none of this is useful, or if the button doesn't respond to a hard press, then it may be because the circuit board has become damaged. This can be fixed with a quick clean and re-soldering, but it is best to have an extra fob in case this method does not work for you.
Circuitry
The circuit board of your remote control may be dirty regardless of whether the buttons on the key fob are working or not. This issue can be fixed through a thorough examination. The most frequent causes of dirty circuit boards is water and broken cases. A damaged case could let water and other debris to get into the circuit board, causing it to short. Water can also eat through pins and vias, which are small connectors on the board.
If you're able to open your key fob and don't mind a little mess, we can de-solder the buttons and then solder new ones in their place. It's also 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 stay in their down position. Soldering the terminals, and putting the button back into place is typically all that's required to return a non-working key fob to working order.
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 when a hole is made in them or if a car door handle or lawnmower runs over them. Most of the time non-remote transponder chip failures could be attributed to blowing fuses.
If you are not comfortable opening the key fob, you may remove the circuitboard and utilize a multimeter to verify that the diode is operating properly. If you're unsure about doing this, head to your local hardware store or the Oreilly's and they'll usually have an RF frequency tester that will determine whether the key fob is transmitting a signal.
Programming
Key fobs take a lot of abuse and aren't impervious to damage. They can break their connection with the receiver inside your vehicle because of shocks or a low battery, requiring reprogramming. A professional auto locksmith or main dealer can reprogram the keyfob to get it working again. In the rarer case that resetting and fixing your key fob fails it could be the time to replace it completely.