TOUCHBAR BACKLIGHT NOT WORKING

Try this:

How to reset the SMC of your Mac - Apple Support

and this:

Reset NVRAM or PRAM on your Mac - Apple Support

If it still does not work, its likely that the mac will need service:

Contact Apple for support and service - Apple Support

zeeshan000 wrote:

TOUCHBAR BACKLIGHT NOT WORKING KEYS ARE WORKING WHILE PRESSING BUT THERE IS NO LIGHT DISPLAY ON TOUCH BAR

If resetting the SMC https://support.apple.com/en-us/HT201295 does not bring it back to life, then you have a hardware issue—

In or out of warranty you can get a free over the counter 'Apple Service Diagnostics' test /assessment

Make an appointment for a "hardware issue"—

https://www.apple.com/retail/geniusbar/

Outside the USA

https://locate.apple.com/country

From iOS device using the app to make a online Genius Bar appointment is easy:

https://itunes.apple.com/us/app/apple-support/id1130498044?mt=8