How to Fix a Key Fob That isn't Working
If your key fob won't work and you're not sure why, you can fix it with some simple steps. The first step is to be sure it's not the backup remote.
If the backup remote is able to lock and unlock your car doors, it is most likely an issue with the main remote. Most problems with car remote keys are caused by battery or circuitry problems.
Battery
It is not uncommon for the battery inside the key fob for cars to wear out. It is relatively easy to change out a battery, although it is essential to ensure you select the correct one and you can consult the owner's manual or talk to the dealer of the manufacturer to find out the kind of battery you require. It is also important to examine the battery compartment, as batteries that are not working properly can release caustic chemicals which can damage the remote. If changing the batteries doesn't solve the issue it could be that there are other issues that require attention by a professional. For instance, if buttons seem stuck or damaged, it may be necessary to disassemble the remote and rebuild its components. You could also try reprogramming your car to recognize the new key fob.
Buttons
Through frequent use, key fobs could wear out and become dirty. This is not atypical however, it can cause buttons to cease working or require a very difficult press to get them to function. This can be extremely frustrating particularly 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 bit of time and a few items you might already have in the home.
First, make sure the batteries are charged 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. Look for signs of corrosion or other signs that buttons are worn out or damaged, like missing paint that is conductive. Use a Q-tip, dipped in alcohol to gently clean any membrane contact that has worn-out or where conductive painting is missing. Avoid rubbing too hard, since this could cause damage to the conductive painting and prevent the button from firing when it is pressed.
Also, be sure to check the battery connector's terminals to ensure a loose solder connection. Soldering them back in place can restore the button's functionality if this is the situation. You can follow the same procedure to restore functionality to any other loose connection within the fob.
If any of the rubber buttons at the front of the keyfob are not working or require being press very hard the graphite disks on the back of the button may have worn out and need to replaced. This is usually done by rubbing a pencil on the disks. This should bring the button back to its original state.
If all of this doesn't help, or if the button does not respond to a hard press, then it may be because the circuit board itself is damaged. It is possible to fix this by cleaning and re-soldering the fob, but you should have another spare in case it does not work.
Circuitry
Whether or not the keys fob buttons are functioning the circuit board in your remote may be dirty. This issue can be fixed through a thorough examination. The most common causes for dirty circuit boards are water and broken cases. A damaged case could allow water and other debris to get into the circuit board, causing it to short. Water can also damage pins and small connectors on the board called via's.
If you are handy enough to open your key fob and don't mind making some mess, we can take the buttons out of their sockets and solder in new ones. Also, you should check the connections between the battery terminals. If they're loose, the buttons could not function properly or become stuck in their down position. Soldering the terminals and buttons back in their place is generally all that's needed to return the key fob that is not working 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 cracking when a hole is made into them or in the event that a door handle of a car or lawnmower runs over them. Failures of the fuse are typically to blame for non-remote chip failures.
If you're not comfortable opening the key fob, remove the circuitboard and use a multimeter to verify that the diode is operating correctly. If i was reading this 're not comfortable with this, you can go to your local Oreilly or hardware store and utilize their RF frequency tester. This will tell you whether the key fob transmits a signal.
Programming
Key fobs are not indestructible and can be damaged by a variety of factors. They may lose their connection with the receiver inside your vehicle due to shocks or a low battery, requiring reprogramming. A professional auto locksmith or a dealer in the main can reprogram the key fob and get it back working again. In the event that resetting or repairing your key fob fails it may be time to replace it entirely.