The phrase "to turn on the lights" means to make the lights in a room or area start shining or get brighter.
Sentences with «to turn on the lights»
The rule will bring more transparency... like turning on a light in a dark room. (mutualfundobserver.com)
What about those individuals living in the developing world without electricity — the 1.5 billion people who can't turn on a light switch much less charge a device? (entrepreneur.com)
Don't turn on the lights or carry on a conversation. (slumbersounds.com)