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 fix it. The first step is to make sure that it's not the backup remote.
If your backup remote cannot lock and unlock the doors of your car, it is likely that the main remote isn't functioning. The most common causes of key malfunctions for car remotes are circuitry or battery issues.
Battery
The battery in the key fob could be worn out over time. It is easy to replace batteries. However it is essential that you choose the right kind. You can consult the owner's manual or contact the manufacturer to inquire about the right type. It is also a good idea to examine the battery compartment with care, as dead batteries sometimes leak caustic chemicals that can cause damage to the remote. If replacing the batteries doesn't solve the problem it could be that there are other issues that require attention by a professional. For example, if buttons appear stuck or broken It may be necessary to disassemble the remote and rework its components. You can also try reprogramming the vehicle to recognize the new fob.
car key repairs to frequent use, key fobs may wear out and become dirty. This is not uncommon however it can cause buttons to cease functioning or require a long press to work. This can be a hassle particularly when you're away from your home and have to turn on your car. Even malfunctioning or worn-out buttons are often fixable with a little effort and tools you already have at home.
First, make sure the batteries are up correctly and that the indentation on the back of the button is filled. Take the remote apart and look over the circuit board. Examine for signs of rust or other signs the buttons are damaged or worn out. For instance the paint that conducts electricity could be missing. Then, using a Q-tip that has been dipped in alcohol, gently clean any membrane contacts that have become worn or have conductive paint missing. Avoid rubbing too hard, because this could damage the conductive paint and block 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 will restore the button's functionality in the event that this is the case. The same process can be used to restore function to any loose connections in the fob.
If any of the rubber buttons located at the front of the keyfob isn't working or need to be pressing extremely 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 over the disks, which should bring the button back to life.
If none of this is useful, or if the button still doesn't respond to a hard push It could be that the circuit board itself has gone bad. It is possible to fix the issue by cleaning and re-soldering your fob, but you should have another spare in case it doesn't work.
Circuitry
If the key fob buttons are working, the circuit board inside the remote could be dirty. A thorough examination is usually enough to fix this problem. Water and broken cases are the most frequent causes of dirty boards. A broken case can let water and other debris into the circuit board, which can cause it to short. Water can also destroy pins and connectors on the board called via's.
If you're handy enough to open up your key fob and aren't afraid of a little mess, we can de-solder the buttons and then solder new ones in their place. Also, it's worth checking the connections between battery terminals. If they're loose, the buttons could not function properly or become stuck in their down position. Soldering terminals and buttons back to their original positions is often enough to bring a non-working fob to a working condition.
Non-Remote Transponder Chips
The sealed non-remote chips are more durable than remote fobs. However, they are susceptible to breaking in the event of a hole being drilled into them or if a car door handle or lawnmowers plows over them. Failures of the fuse are typically the cause of non-remote chip failures.
If you're able to remove a key fob that is sealed and are able to bear the mess, you can remove the circuit board and test the fuse using a multimeter for proper diode function. If you're not sure with this, you can visit your local Oreilly or hardware store and utilize their RF frequency tester. This will tell you whether the key fob is sending signals.
Programming
Key fobs take many abuses and aren't indestructible. They can break their connection with the receiver inside your vehicle due to shocks or a low battery, requiring changing the program. A professional auto locksmith or main dealer will be able to reprogram your key fob to get it working again. If resetting or replacing the keyfob is not working it is possible to replace it.