How to Repair a Remote Key
Although most remote key fobs come with impressive battery lives they will eventually wear out. Sometimes it's simple to replace the batteries inside the device, however sometimes the problem can be more severe.
A quick fix that can aid is to disassemble the remote by cleaning the buttons and flexing them in and out. These techniques might be all you need to get the key fob to work.
Battery
Car key remotes are powered by CR2025 or CR2032 batteries, and they can often be swapped out when the fob is functional. If not, you can inspect the battery terminals or buttons to determine if there are any parts that are loose. Often the terminals and buttons can be repaired by soldering them back into place however you'll need be aware of the exact kind of battery your fob uses.
If you're not sure if the battery is the problem you can use a backup fob to unlock or start your vehicle. If you can then it's time to replace the primary fob. If not, a professional check is required to determine why it's not functioning properly. It could be a simple reconfiguration, or it may require other types repair. You might also discover that your vehicle has forgotten the fob. This isn't something you can do on your own.
Case
The case of a remote key is the plastic case that surrounds it and usually comes with the button pad replacement. It is crucial to get a new case as the original will probably be quite dirty and it is vital that the circuit board is installed correctly in the case. The circuit board is the main component of the key fob. It can be tested with a normal multimeter by setting it to the RF (radio frequency) mode and then holding a radio scanner tuned to the same frequency the key fob is using next to it, watching for pulsing signals upon the button's presses.
Check the contact points on the buttons on the keypad. They may have become loose over time or have been damaged. By carefully re-soldering repair car keys into their original position can usually restore them to their original function unless they break completely.
Buttons
If the buttons on your key fob are no longer working or are difficult to push, you can purchase a new dorman or motormite remote key housing on the internet at a an affordable cost for your model/year/make. Then, pop the circuit board out of the old case and into the new one. It is possible to adjust the position of your board on some models. You can then use aluminum foil using double-sided tape to adhere it to the black contact points on the buttons.
Programming
The key fob and receiver inside your car are linked however this connection could be damaged. A professional will assess your vehicle to determine its year, make, and model. They'll then use specialist equipment to reconnect or program a blank transponder chip or fob (or copy the key if possible). They will then test the remote to confirm that it functions.
It is important to be careful when reprogramming a blank key, as the process can be complicated and different manufacturers require certain steps that are slightly different. It is also possible to miss a step or delay too long before leaving the programming mode, which is why it is recommended to hire a professional with comprehensive knowledge of the security system of your vehicle to reduce the chance of damaging the car. Certain key programming tools can also identify diagnostic trouble codes on your vehicle. This can assist you to solve other issues.