No matter how long you've had your car, there's always something new you can learn about the vehicle - from a trick to open the windows using only your keys, to a hack to help find it when you've lost it in a car park.
Recently, drivers have been left stunned by the discovery that there's a 'magic' button in some cars that will defrost the windscreen in a matter of seconds and now it seems there's another button that many people have been stumped by.
Certain vehicles have a little button, that looks like a power button, located on the bottom of their rear-view mirror and numerous people have turned to the internet in the hopes of finding out what exactly it does.
