Press the F5, F9, or F11 key to turn your HP laptop keyboard light on or off. Some HP laptops need the Fn key pressed with the light key to activate the keyboard light. If these keys don't work ...

Instead, you need to go to System Preferences > Keyboard. On the Keyboard tab, check the box for Turn keyboard backlight off after ____ of inactivity. Your options range from 5 seconds to 5 minutes.