How to Repair a Remote Key
Although most remote key fobs come with impressive battery lives they will eventually wear out. Sometimes it's as simple as changing the batteries inside the device, however sometimes the issue can be more severe.
Take the remote apart and clean the buttons. Then bend them in and out. These techniques may be all that you need to get your key fob back in working order.
Battery
If the fob is working you can replace the CR2025 or CR2032 battery. If not, inspect the battery terminals or buttons to determine if they are any missing parts. It is usually possible to connect the terminals and buttons back into their original positions. However, you will need to know what kind of battery is being used in your fob.
If you're unsure whether the battery is at fault, use a backup fob to unlock or start your vehicle. If you can, it's probably time to replace the primary fob. If it's not then you'll need to have a professional examine it to find the problem. It could be as simple as reprogramming, or it could require other types of repair. You may also find that your vehicle has forgotten the fob. This isn't something you can fix on your own.
Case Study
The case of remote keys is the plastic case that surrounds it and usually comes with the replacement button pad. It is recommended to purchase an entirely new case as the original will likely to be extremely filthy. It is vital that the circuit board in the case is properly positioned. The circuit board is the main component of the key fob and is tested using a standard multimeter by setting it to RF (radio frequency) mode and holding a scanner tuned to the same frequency that the key fob operates on next to it, listening for signals that pulsate upon the button's presses.
Check the contact points of the buttons on the keypad. love it may be loose over time or have been damaged. Carefully soldering them back in place can often return them to their original function unless they snap off completely.
Buttons
IF your key fob buttons no longer work or are difficult to press, a dorman or motormite remote key housing replacement could be bought inexpensively online for the year/make/model you have. Then, you can take the circuit board from your old case and put it into the new one. On some models you may have to adjust the board's position slightly. You can then use aluminum foil with double sided tape to adhere to the black contact points on the buttons.
Programming
The key fob and receiver in your car are paired however this connection could be ruined. A professional will assess the car to determine the make model, year and model. They will use specialist equipment to re-pair or program an empty fob or transponder chip (or clone a key in the event that it is possible). Then they test the remote to make sure it functions.
When programming blank keys, it is important to take care. The process can be complicated and each manufacturer comes with slightly different instructions. It is also possible to miss a step, or take too long to exit the programming mode, therefore it is recommended to work with a professional with comprehensive knowledge of your car's security system to minimize the risk of damaging the car. Some key programming tools can also detect diagnostic trouble codes on your vehicle. This can assist you to fix or resolve other issues.