mousepad light not able to switch off

Hi, 

I am facing a problem with my mousepad light on the laptop. The light on the mousepad was not able to switch off despite pressing the sensor twice. Even though, the light on "switch on" on the mousepad, but I was still able to use the mousepad to move the mouse/ scroll the internet.  Can anyone give me some advice on how to switch the light off on the mousepad? 

Thanks