Mac Keyboard lights sometimes not working..

Dreamnine

... usually at night whenever I want to compose an email.

This seems pretty random. On startup, the backlights always come on, but at various times of the day they'll switch off and won't respond to their assigned buttons, F5 and F6.

The machine is a 2016 MacBook 12.

System

Keyboard backlighting does automatically turn off during the day depending on the level of brightness and you'll find if you cover the webcam they'll start working again.

Try doing a SMC reset.

1. Shutdown your MacBook Air / MacBook Pro
2. Connect the power adapter to the Mac
3. On the MacBook / Pro keyboard, hold down the Shift+Control+Option keys and the Power button at the same time
4. Release all keys and the power button at the same time; the little light on the MagSafe adapter may change colors briefly to indicate the SMC has reset
5. Boot your Mac as usual

Here's the key sequence to hold down:



Once you've done it you'll need to go back into System Preferences and reset any power management settings back to what you want them.

Dreamnine

Thanks, I've done that and all seems well at the moment.