Replacing a key fob battery can be a bit tricky. It's best to use a local professional to ensure that the new battery is fitted correctly. Please note. You will need to call into a local locksmith shop to get your car key battery changed. It is unlikely that a mobile auto locksmith will offer this service.
If your remote key fob has stopped remotely opening the doors, it’s possible that the battery needs replacing. Also, if your car key only opens the doors intermittently, the battery cell may be getting running low.
You should be aware that if the battery in your fob is dead, you should still be able to start the car. A dead battery in your lkey will result in the remote locking and unlocking functionality stopping. In some keyless cars, this may not be the case.
A local specialist will be able to check the existing signal, change the battery and ensure it is sending a signal once the new battery is fitted.